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Author Topic:   Thru Hull Replacement
derf posted 11-15-2005 04:20 PM ET (US)   Profile for derf   Send Email to derf  
[Note--unfortunately many of the pictures mentioned below are no longer available from the linked source. An alternative source is given below.--jimh.]

My Outrage 18 needed new thru hulls. I got the parts from Sue at TC. I bought the tool, too. Here is a pic of tool and 6" tube:

Get extra tubes, they are cheap. You can get tubes with one flange already done or your can get plain tubing and do you own flanges on both ends. I'm using a pre flanged tube in the pics. Start with the longest holes so you can reuse the tube if it doesn't work right. I'm doing the anchor locker thru in the pics. It is the longest. When I goofed, I just removed the tube and will try and use it for the transom or stern area, as those tubes are shorter. Removal consists of using pliers or ViceGrips to bend the flange in toward the middle, so the tube can be pulled out. Get extra Orings, too. I did this by myself but a helper would really make things quicker, unless you like climbing in and out of the boat alot.

Here is the thru hull before:

Here is a pic of the old thru and the tool used to remove it:

Once removed you will want to clean up the fiberglass around the hole where the Oring will seal. Then you will want to cut the tube to length. This is somewhat tricky as you want to have enough to flare properly but not too much or it won't seal the Oring.

Don't forget the Oring:

The tool came with one bolt. It will work for some, but not all of the thru hulls. You can get longer bolts for the various length thrus. I used a piece of 1/2" all-thread that I had bought for my lifting eye hardware.

Here is a pic of the inside during installation.

OOPS! That one was going well and then split:

Time to start over with a new tube. I added some lube this time and it seems to have helped. I used Pam cooking spray because it was handy. I use Pam when turning on my metal lathe, too, so don't knock it......

Here is the finished product:

I plan to clean up and re-gelcoat the bottom after I patch some holes here and there.

I would rate the results as very good. The thru hulls are definitely servicable. Next time I think they will turn out better. And, next time I plan to try plain tubing from Mcmaster-Carr. The tubes Sue sent me had "China" stamped on them. They work fine. But, I think a better grade of brass might work better.

Please feel free to post comments or point out any mistakes I have made.

gvisko posted 11-15-2005 04:51 PM ET (US)     Profile for gvisko  Send Email to gvisko     
how far do you let the tube extend for the o ring before
you compress it? also I think Tom C said you should heat
the tube before you compress it and it wont split. did you do this?

george viskovich

derf posted 11-15-2005 05:07 PM ET (US)     Profile for derf  Send Email to derf     
I didn't heat it. I may try that next time.
I would say I cut the tube to about 3/16" beyond the oring before compression.
fla656 posted 11-15-2005 06:19 PM ET (US)     Profile for fla656  Send Email to fla656     
Thanks for taking the time to post this, GOOD JOB!!
Casco Bay Outrage posted 11-15-2005 06:33 PM ET (US)     Profile for Casco Bay Outrage  Send Email to Casco Bay Outrage     
Nice job. Thanks for the photos!!
bsmotril posted 11-15-2005 08:39 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Heating brass is not like heating steel. When you heat it and try to work it, you risk cracking the metal. Brass becomes very brittle when heated. Brass Ammunition cartridge cases are all cold drawn, resized, and crimped with cold brass. You can even neck down a .40 cartridge case mouth to .17 if you want using a series of 6-7 dies. Don't heat it, you'll break it when you roll the edge over. BillS
RJG posted 11-15-2005 09:03 PM ET (US)     Profile for RJG  Send Email to RJG     
This is really good stuff! I need to replace one on my 22 Revenge.
Tom W Clark posted 11-15-2005 09:14 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
I spent this afternoon replacing brass drain tubes in Brad Bringedahl's Revenge 22.

Rule #1: Anneal the brass! To do this you heat it red hot and then quench it, i.e. let it cool. It does not matter if it cools down in the air or if you throw it in a bucket of water, either way will work. The brass becomes much easier to work and will not split like derf's photo shows.

derf posted 11-15-2005 10:13 PM ET (US)     Profile for derf  Send Email to derf     
All due respect to everyone. It sounds like TWC has done the heating thing with good results.

BillS, I, too, have a shooting hobby so I can relate a little. I don't reload, though. However, isn't the brass heated each time it is fired? Again, I'm not trying to stir up anything. What TWC is saying makes sense. He doesn't say heat it and work it while it is hot. Annealing would probably be good for brass before flaring. I'm willing to try it, especially if someone like TWC suggests it, having done it himself, I'm sure.
I think the annealing would help "normalize" then end that has just been subjected to cutting stresses, if nothing else.

I hope no one takes offence. This is a discussion forum and I'm not trying to question anyone or start any "stuff".

derf posted 11-15-2005 10:15 PM ET (US)     Profile for derf  Send Email to derf     
I spent this afternoon replacing brass drain tubes in Brad Bringedahl's Revenge 22.

I wish you had spent the morning helping me do mine. Then I wouldn't have split one and it would have taken about an hour. If only you were in Baton Rouge.

bsmotril posted 11-16-2005 08:27 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Annealing brass is very quirky compared to other metals. It goes from a solid, to liquid in a flash. Red hot is way too hot also. The color you are shooting for while heating is blue-ish, and thould be 650-675 degrees. McMaster Carr sells a temp melt crayon that melts at 650, which is what I use for my cartridge cases. And you are absolutely correct with the quick quench, which is just the opposite of how you anneal steel.
Tom W Clark posted 11-16-2005 09:38 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Nothing quirky about it. No need for a melt stick. Just heat those suckers up with a propane torch till they start to glow and throw them in a bucket of water. Simple as that.

To anyone contemplating this project I would advise them to buy the brass tubing from McMaster-Carr. You can buy the O-rings from them as well.

I bought a flaring tool from Hamilton Marine some years ago water after I cut up CSW. I used that hull as a testing platform when my flaring tool arrived. I bought some off-the-shelf brass tubes and tried to install them. I found the brass would split about half the time. It was David Thickens who pointed out that you need to anneal the brass first.

If you anneal the brass, it becomes a much easier proposition.

I also suggest using a sealant in conjunction with the O-rings. Yesterday we used 3M 4200 FC which worked just fine.

Brad and I were using my "power flaring tool" which I have to say worked damn well.

derf posted 11-16-2005 11:10 AM ET (US)     Profile for derf  Send Email to derf     
I like that power flaring tool. I was thinking of making some kind of hydraulic tool. But, if each hull has less than 6, the expense or a power tool becomes unnecessary.
BTW, what are the part number from McM-C on those tubes and O-rings, if you have them handy?
Plotman posted 11-16-2005 12:45 PM ET (US)     Profile for Plotman  Send Email to Plotman     
Just type brass tubing into the search on the McMaster site. Or under the "Pipe, Tubing, Hose" section on the main page click on metal tubing and look for brass. You want the 0.035" wall thickness in either 1.00" or 1.25" OD.
1" Item number is 8950K791. $13.11 for a 3 footer, or $19.60 for a 6 foot chunk.

The o-rings I got were 3/32 in cross section, 15/16 ID. to give a snug fit over the tubing. This is a "dash 119" size. 1" ID is the "dash 120. About $4 for a pack of 100 in Buena material, $8 in silicone.


David Livingstone posted 11-16-2005 04:30 PM ET (US)     Profile for David Livingstone  Send Email to David Livingstone     
Derf, great job.

Jimh, could you ever massage the thread a little and put it in the reference section?

Thanks guys for more great information,


Tom W Clark posted 11-16-2005 06:50 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
The "power flaring tool" I made is nothing but a Campbell Hausfeld air hammer that costs less than $20 with one it its four rivet sets cut off. Of course one needs an air compressor, but I'm a contractor so I have a couple portables kicking around. You don't need much.

You do need to shorten one of the two dies from the flaring tool. Heck I paid Hamilton Marine more for the flaring tool than the air hammer!

I used EPDM O-rings from McMaster-Carr. The silicone ones do not some in black and didn't sound like a good fit. The EPDM are supposed to be tougher than the Buna-N.

The dash number of the 1" O-rings I used is 213, not 019. This is what David told me to get! They are 1/8" in cross section and a little less than 1" i.d. for a snug fit. David, check your notes.

Tom W Clark posted 11-16-2005 10:15 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Here is a photo from yesterday that shows how nice the flares can turn out. I believe this is the inside of the stern sump in Brad's Revenge 22.

You can see the roll is well past 90 degrees of deflection. It is important to keep rolling the brass until it captures the O-ring. A flared lip that is only turned 90 degrees will not lock the O-ring in place.

In order to get a good roll like this I found it was better to leave about 1/4" of brass tubing extending past the hull instead of 3/16".

The photo also shows the 3M 4200FC we used as a sealant. The photo was taken immediately after we wiped the excess caulk off with an acetone saturated paper towel.

I also coated the shank of the brass tubing where it passed through the fiberglass of the hull. In this sump area the 'glass was 3/8" thick. The drain at the bottom of the fish well passes through about 3/4" of 'glass and is very near the keel of the boat. That extra thickness of 'glass down there was a good illustration of how Whalers are reinforced in their keel areas.

There is no point in coating the entire length of the tube and gluing it to the foam.

derf posted 11-17-2005 12:15 AM ET (US)     Profile for derf  Send Email to derf     
That's a nice flare, Tom. The one in my sump area turned out that nice. The other one wasn't quite as good.
derf posted 11-17-2005 12:24 AM ET (US)     Profile for derf  Send Email to derf     
In order to get a good roll like this I found it was better to leave about 1/4" of brass tubing extending past the hull instead of 3/16".

I think we are in agreement there. I meant about 3/16" beyond the oring or 5/16" beyond the hull, if the oring is about 1/8".

Next time I plan to anneal the brass and I'm sure that my results will be perfect.

alfa posted 11-17-2005 01:55 AM ET (US)     Profile for alfa  Send Email to alfa     
Very nice job.
And many thanks for pictures and tips.
Kencvit posted 11-17-2005 04:13 AM ET (US)     Profile for Kencvit  Send Email to Kencvit     
This may be off topic here but why brass/ metal thruhulls over the poly /plastic . What is the advantage. I know the friction fit poly ones are easy to install and seal, but beyond that why should one choose one over the other in reference to a boston whaler boat.
Tom W Clark posted 11-17-2005 09:43 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

There are several advantages to the brass drain tubes, foremost among them is the ability of the brass to easily conform to a non-perpendicular surface.

With the flaring die shortened it is free to pivot to the side and flare a drain tube at an angle to the tube itself, which is necessary more times than not on classic Boston Whalers. The 10" drain tube from the fish well to the splash well in the 22s has an angle of over 10 degrees on both ends. A plastic drain tube with a preformed lip will not accommodate this angle.

The second big reason to use the Brass tubing is its low profile after the flare is formed. The plastic tubes have much bigger head and necessitate a larger clam shell for those used on the bottom. This in turn means more turbulence and drag under the hull.

Retrofitting a plastic drain tube (or cast bronze through hull) will necessitate drilling a significantly larger hole through the hull. Once you have done this, there is no going back.

Additionally I think there is the aesthetic desirability of having something original. They just look nice.

I think that a lot of Whaler owners have been afraid of this project for too long. It is my hope to demonstrate with other that this project can be done inexpensively and easily with the right tools.

derf posted 11-17-2005 10:36 AM ET (US)     Profile for derf  Send Email to derf     
Yes, I think thru hull replacement can be done by anyone with a minimum of mechanical ability. If you can change a flat tire or change your own oil, you can probably change your thru hulls.
Eagleman posted 11-17-2005 12:16 PM ET (US)     Profile for Eagleman  Send Email to Eagleman     
Great job on the through hull fittings. Great information to have on hand when it's time to replace these fittings.
derf posted 11-17-2005 12:46 PM ET (US)     Profile for derf  Send Email to derf seems to be down. Here are alternate pics that are smaller for you dial-up guys.

vkr posted 11-18-2005 08:55 PM ET (US)     Profile for vkr  Send Email to vkr     
This is the best thread I have read on this subject. It would be great to tweak it up a little and make a reference section article out of this information. Adding part number detail for the flaring tools and all the components, along with where to purchase information would be great. Also, information on the OEM brass tubing inside diameters (I.D.) for various Boston Whaler models would also be helpful. I have the following questions:

My 1986 Boston Whaler Outrage 18 has approximately 1 1/8” I.D. transom drain tubes if I am not mistaken. However, I believe the sump drain tube and forward locker drain tube are 1” inside diameter. Can anyone confirm the various sizes for the Outrage 18 ? My boat is in storage and I would like to order some components.

Are there different flaring tools available for various drain tube inside diameters (i.e. 1” ID or 1 1/8” ID) ?

If I am not mistaken the hull surfaces (most likely exterior hull surfaces) are not perpendicular to the drain tube hole and/or drain tube. Does the flaring tool float enough on the ½” bolt to accommodate this angle ?

Joe Kriz posted 11-18-2005 09:12 PM ET (US)     Profile for Joe Kriz  Send Email to Joe Kriz     

The larger size is 1 1/4 inches.. out the transom on many models.

I have 3 of them out the back of my 1985 Outrage 18.

I had 3 of them out the back of my 1986 Outrage 18.

I had 2 of them out the back of my 1989 Outrage 20.

vkr posted 11-20-2005 11:49 AM ET (US)     Profile for vkr  Send Email to vkr     
Joe, Thanks for the info. I'll measure mine carefully. I thought I came up with an odd 1 1/8" I.D. last time I quickly measured them.

derf and/or Tom, Can you help me out with the last two questions in my above post? Thanks

kingfish posted 11-20-2005 12:49 PM ET (US)     Profile for kingfish  Send Email to kingfish     

Tom answered your second question before you asked it, above your post, in the affirmative.


derf posted 11-20-2005 12:53 PM ET (US)     Profile for derf  Send Email to derf     
The two sizes, 1" and 1-1/4" are OD measurements. Your 1-1/8" ID tube is a 1-1/4" tube. There are only two sizes on classic Whalers.

To answer your Qs:
There are different sized tools for each size of tubing.

You are correct about the in/out surfaces not being parallel. The tool compensates for this somewhat. But, the surfaces are close enough in parallel to make sealing possible without any offset angle of flare installation. I thought about maybe cutting an angle on the end of the tube before flaring but I don't think it would help. The tube is round and the tool is round. The trick is cutting the tube to the right length. Then the flare will seal correctly.

Kencvit posted 11-20-2005 10:49 PM ET (US)     Profile for Kencvit  Send Email to Kencvit     
Tom Clark,
Thanks for your reply .
Derf and others,
Thanks for the pictures and explanations
Tom W Clark posted 11-22-2005 12:19 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Yup, 1" and 1.25". These are OD dimensions as derf points out. Because the flaring operation may buckle the tubing slightly, the i.d. may seem smaller still.

If there is a flaring tool for the 1.25" tubing, I haven't found it yet. I'm having my agents work on turning one for my power flaring tool on a lathe.

The 1/2" bolt or all-thread will not allow any significant angle to be achieved on the end of a tube. Most tubes in Whaler hulls have some angle to them so this tool does not work well except in the few instances where the tube is perpendicular to both the inside and the outside surfaces.

You can use the dies at an angle if you use smaller diameter all thread and a custom wedge.

When Brad and I did the 10" tube in his Revenge 22 that goes between the fishwell and the splashwell we realized it had a 10-15 degree angle on both ends. Because there is only about 2.5"-3" of room in the bottom of the splashwell, the tube had to go in from the fishwell side.

This meant we could not use the air hammer on this tube. We had to use all-thread and because of the angles, we had to go buy some 3/8" diameter all-thread and then I made a wedge from a scrap of 2x4. With several fender washers to help distribute the load, we were able to draw the flare in the tubing quite well.

vkr posted 11-22-2005 07:40 PM ET (US)     Profile for vkr  Send Email to vkr     
Tom, Thanks, your answers address the questions in my first post above.

The charge for drain tube replacement in my area is $85.00 per tube. It would be interesting to see just what the Boston Whaler dealerships use in the way of a flaring tool. Is there a flaring tool kit out there (possibly supplied by Boston Whaler) that provides the dealerships a means of addressing the various angles one encounters on various whaler hulls? Possibly, there is one that comes with various angled wedges similar to what you used.

derf posted 11-22-2005 07:41 PM ET (US)     Profile for derf  Send Email to derf     
I don't know who your agents are. But, if you send me a piece of 1 1/4" tubing and some dimensions of your air tool mod, I can probably turn out a flaring tool on my lathe.
Tom W Clark posted 11-22-2005 09:35 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
I am sure somebody makes an articulated flaring tool, but I don't know where to find it.

If I were a machinist and had a lathe, it would be very easy to make such a tool, or modify the simple one we all have to work with the angles encountered in the typical Whaler.

All one would have to do is taper the "front end" of the flaring dies so it could cant to the side enough to accommodate the most extreme angles in a Whaler.

Then you would need two steel ball (ball bearings, perhaps?) that were bored to accommodate the all-thread one were using.

If we take the off-the-shelf flaring tool from Whaler or Hamilton Marine we see the dies have a hole through them of .51" according to my dial calipers. So buy two 3/4" steel ball from McMaster-Carr an bore a .51" hole through them and thread you all-thread through everything and away you go!


My agents are Brad and his next door neighbor, code name: "The Jeweler"

The Jeweler has a lathe. But so do you. Maybe you would like to take on this project?

derf posted 11-23-2005 09:36 AM ET (US)     Profile for derf  Send Email to derf     
Perhaps. Let me see what Enco has off the shelf that might work. Ball bearings are very hard and would probably be difficult to bore and/or part. Enco sells washers and such for angled applications. You may browse and see if you can find something. You may also consider having flats on the outside diameter of the flaring tool so you can keep it from turning and maintain the angle you want. Let me do some research.
derf posted 11-23-2005 11:45 AM ET (US)     Profile for derf  Send Email to derf     
Maybe something like this for the ends:

If you go more than 10 or 15 degrees on either end it probably won't make a good flare anyway, no?

Tom W Clark posted 11-23-2005 11:51 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Yeah, that looks good. Why not order some and we can see just how far they will tilt?

I think the most extreme angle on any drain tube in a Whaler hull are the side bow lockers in the Outrages. I don't have any in my Revenge so I can't measure the angle there. Anybody with an Outrage care to measure this "worst case scenario"?

Tom W Clark posted 11-23-2005 12:05 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Nope. Won't work. As soon as there is a change in the angle, the holes no longer align. Maybe it would work if 3/8" all-thread were used but I still worry about the range of angle.
bear99 posted 11-23-2005 08:52 PM ET (US)     Profile for bear99  Send Email to bear99     
Tom ,

We have 2 1.25's ready to roll.

Ken says his codename should be "Clockmaker".


Graham posted 11-27-2005 07:10 AM ET (US)     Profile for Graham  Send Email to Graham     
Good article.

Just wanted to know if you fited a "clam shell" over the hull side of the tube? Any Pics

My 1982 22' Outrage has had all the through hull fittings sealed by previous owner.


derf posted 11-27-2005 01:27 PM ET (US)     Profile for derf  Send Email to derf     
I replaced the clamshell on the starbaord side sump area tube. I used a SS unit from West Marine that used three screw mount instead of five.
Martino posted 01-13-2006 08:51 PM ET (US)     Profile for Martino  Send Email to Martino     
Does anyone know what Tom Clark is describing as his modifications to the air hammer to turn it into the flaring tool? I can't figure what rivets he is talking about removing. How is the die mounted in the tool? How do you hold the tube in place when you use the air hammer from the other side?
deepwater posted 01-13-2006 09:07 PM ET (US)     Profile for deepwater  Send Email to deepwater     
derf ? did you or could you feel the flanges forming?,and do you think the lube used in resizing large cal brass bullet cases would help prevent splitting ?
derf posted 01-14-2006 01:16 AM ET (US)     Profile for derf  Send Email to derf     
Case lube would not hurt. Grease wouldn't hurt, but might be messy. But, I think annealing is the way to go to avoid splitting. I didn't anneal last time and had some splitting. Next time I will definitely anneal. I am confident that the anneal will solve the splitting problem.

As far as feeling the flange while forming, I didn't really. But, the way the tool is made, you can easily see the flange forming.

You can use the tool for the cost of postage there and back, so long as I get it back within a reasonable time period.

Tom W Clark posted 01-14-2006 01:12 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I posted this link above but I guess you missed it. Here it is again:

The retaining spring has been removed and I have cut off one of the sets so I could slide the modified die over it. It works very well even on the dreaded forward drain tube on the 22 which meets the outside of the hull at a profound angle.

Tom W Clark posted 01-14-2006 01:16 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Here is a photo showing the air hammer in position as it formed the flare:

Here is the forward drain tube immediately after forming the flare. This tube meets the outside of the hull at a 13 degree angle. The gun easily handled the odd angle.

Martino posted 01-14-2006 08:46 PM ET (US)     Profile for Martino  Send Email to Martino     
Sorry if I seem a little dense, I really appreciate your help. I assume that the one piece of the die is firmly mounted to the air hammer? In the article, it said you had to shorten the die. What did that mean? How are you holding the drain tube while you are hammering it? (I started doing my 22' Revenge about a year ago, cracked three tubes, started cussin, and it's been sittin ever since. Not even the local Whaler dealer ever told me about annealing the tubes prior to use. They act like they have never seem a brass drain tube.) I'm envious when I see the outstanding job you did with your airhammer.
Tom W Clark posted 01-15-2006 03:05 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

No, the set and the die are not firmly held in the gun. There is no way to make use of the retaining spring with this set up so if you point the gun down the parts simply fall out; a small nuisance.

I shortened the die by cutting it in half along its length. Examine the photo of the gun I've linked to above. There you will see the typical flaring tool partially dissasembled. One die is still on the bolt, the other is on the air hammer.

If you compare these two dies, you will note that the one on the air hammer has been shortened.

This is necessary because if it is not shortened, you will not be able to angle off to the side at all, the "snout" of the die fits tighly in the tubing and will not angle at all.

I have since actually bevelled the shortened die some more to allow it flare tubing at the more extreme angles. I still think I need to whittle it down even more. I will post some photos when I really get it dialed in.

To create the first flare on each length of tubing, I start by cutting it at the approriate angle. Then I de-burr and sand smooth the edge of the tubing. Then I anneal it. Now I hold the tube in my left hand and the gun and die in my right hand.

Activating the air hammer, I make the flare in only a few seconds.

Once the pre-flared tube is in the hull with O-rings and caulk in place I place the air hammer in position and fire away. I have a helper (Brad) holding a block of wood over the other end of the tube on the inside of the hull while I'm flaring the outside. It's a remarkably easy process.

derf posted 01-15-2006 04:55 PM ET (US)     Profile for derf  Send Email to derf     
The right tool makes the job easier.
Those are some good looking flares, Tom.
Nice job with the tool, too.
devildog posted 01-16-2006 08:16 PM ET (US)     Profile for devildog  Send Email to devildog     
Nice job Derf & Tom,

This topic brings up a question. It looks like there were some through hulls removed and glassed over on my Outrage 22. I assume the anchor locker had two factory drains. One overboard and one aft to the next locker. Am I correct?


Tom W Clark posted 01-17-2006 12:23 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I think there should be four through hull drain tubes in the bow of your 1980 Outrage 22. There should NOT be one between the two large lockers, just one drain in each compartment.

See: html#selfBailing

devildog posted 01-17-2006 11:52 AM ET (US)     Profile for devildog  Send Email to devildog     
Thanks Tom,

I've read that section of the manual but wasn't sure about a through - bulkhead tube. There is some evidence of a repair in that location. Good eye on the year of my Outrage. Memory or research?


joncon posted 01-26-2006 11:14 PM ET (US)     Profile for joncon  Send Email to joncon     
OK this is an area “new thru-hull fittings” on my boat “85 22’ Revenge WT” that has bewildered me or should I say scared me over the last year's rebuild of this boat. I’m not sure where to punch a dang hole in the hull! I fish offshore have a transom mounted “starboard side as low as I can get it without causing drag/rooster tails” depth/sounder/fish finder transducer that looses all data in medium swells. So I have to put a thru-hull to stop this frustration but where do I drill? The fish well scares me and all other areas of the transom beam seem to thick, maybe in the sump pump area but will I get electronic feed back or interference? It’s a kick in the head; I have super nice Furuno electronics and can not get the max out of the equipment and the installer said the hulls to thick to put a thru-hull transducer in the most effective area so try to live with a transom mount. Anybody give me a clue please, I’m an old fart 2 left hands “sometimes steady” and I need to see the bottom once in a while even if its 2000’.
steel120 posted 03-11-2006 07:11 PM ET (US)     Profile for steel120  Send Email to steel120     
Derf; Tom and others on board.

Want to thank everyone for there help here on sources, an Tip/techniques to install the brass thru hull drains.

I order the tubing from McMaster-Carr and the Tool from
the Shipstore..MCMaster-Carr products were ordered on Sunday evening, and arrived on Tuesday morning..Great service, the Shipstore products were ordered the same time, and they arrived on Friday.

So this afternoon, I installed 4 of the 5 1" drain tubes..
I did not get to the 5 one, since I have some wiring for the depth gauge running thru the tube, so tomorrow, I will
remove the wiring that runs from the console to the transducer..Ug..

My Tip or suggestion on cutting the tubes...I have a 32 teeth to the inch hack saw, however, I had trouble staying
on the line with the saw. I tried my Dremel Cutoff abrasive blade..Worked very good, I could follow the line to the "T". All of my tubes has some sort of angle on both
sides. I scribed a line, then drew an offset from that the
recommended 5/16". Used the 213 O'rings and 3m2400..

1 out of the 5 old tubes was competely corroded. The other
4 units the O'rings were dried out completely..No bad wood on stern, and the Anchor locker up front, the Foam was dry and lucky after 23 years..Orginal owner of the 18' Outrage.

Thanks to All..Bob...Steel120

BT Whaler posted 03-12-2006 11:29 PM ET (US)     Profile for BT Whaler  Send Email to BT Whaler     
The knowledge from reading this whole thread is going to be tremendously useful to me. I'm hoping that this might be the right time to ask. My 79 Outrage has no thru hull drainage and the rain collects in the bow locker. What I would like to do is drill a new hole and install a tube for drainage but I'm afraid that if I don't get the angle right that I might wind up drilling thru a strate or a stringer. Or if I drill from the outside in I may miss the side of the storage compartment or not get close enough to the bottom. Has anyone ever installed a new drain? Or does anyone have any ideas on how to go about this?
Tom W Clark posted 03-12-2006 11:42 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The old 21s did have a drain from the bow locker but it was not a through hull. The drain was a small diameter tube molded into the hull that went to the bilge area in the stern. Those drains always clogged up over time.

I think it is an excellent idea to add a through-hull in your bow locker. It should be easy to do. I would drill it from the inside after verifying that you will not encounter any interference as you describe. I should think some careful measuring would tell you the approximate spot on the exterior that you would poke out at with the new hole.

Be sure to add a clam shell ventilator in front of the drain. You want the Perko medium (2" I think) chrome plated clam shell ventilator. This piece of hardware serves as protection for the drain tube and acts as a venturi to suck water out of the bow locker when the boat is in motion.

Whaler had Perko drill two extra holes in these clam shells to make them more secure. It is easy to drill these two extra holes yourself. draintube2.jpg draintube1.jpg

Tom W Clark posted 03-12-2006 11:44 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I am delighted to hear that you found this information useful and that your Outrage 18 now has nice new drain tubes.

DeeVee posted 03-31-2006 04:29 PM ET (US)     Profile for DeeVee  Send Email to DeeVee     
I was at the Mcmaster Carr website today to research/order the drain tubes for my 1989 Outrage 22.

The wall thickness of the 1" tubes can be ordered at .032 or .065. I believe the correct wall thickness for the through hull tubes is .032. Am I correct?

The wall thickness available in the 1.25" tubes is .065. I guess this is the only choice, so that must be the correct item for the splash well drains?


Doug Vazquez

hubmachine posted 03-31-2006 06:52 PM ET (US)     Profile for hubmachine  Send Email to hubmachine     
so, has anyone figured out the angled flang for the bate well and splash well on the early 80s outrages?
working on my v22. hit the brickwall on the batewell/splashwell

many thanks

Tom W Clark posted 04-01-2006 01:21 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
The drain tube replacement for the rear fishwell in the early 22s is described above.
Tom W Clark posted 04-01-2006 01:43 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The wall thickness for both the 1" and 1-1/4" brass tubing is .032". McMaster-Carr sells this thickness of tubing in both diameters.

The McMaster-Carr part number for the 1-1/4" diameter brass tubing (3 foot length) is 8950K832

I wanted to add this bit of info to this thread (it is mentioned in some other threads): There is a 1-1/4" flaring tool available. It s made by Moeller just as the 1" flaring tool is. The best price I have found for both these tools is from

sweetrevenge posted 04-01-2006 07:23 PM ET (US)     Profile for sweetrevenge  Send Email to sweetrevenge     
Tom I replaced all my brass drain tubes in my 1987 20' Revenge, but instead of using the O ring seal, I used 5200. What is the advantages or disadvantages between the 5200 and the 4200FC... Scott
Tom W Clark posted 04-02-2006 01:04 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I think you will get a more positive and durable seal if you use BOTH the O-rings and caulk. But you didn't ask about that so let me address your question.

3M makes a huge number of sealants. In recreational boating there are four related polyurethane caulks that we have all heard of and are familiar with, 5200, 5200 FC (Fast Cure), 4200 and 4200 FC (Fast Cure).

As the name implies, the "FC" version of these caulks cures faster, overnight under normal conditions. The "regular" versions can take a day or several to cure.

5200 has a greater adhesive quality, though 4200 sticks pretty well itself. Some consider 5200 to be non-removable, but my experience suggests that sometimes it is and sometimes it is not. It depends of the amount of caulk and the surface area of the application.

As a practical matter, it makes no difference for these drain tube O-rings. My slight preference would be for 4200 so if the tubs ever needed to be replaced again, the prep work might be a little easier. But I certainly wouldn't let the lack of one or the other of these caulks cause me to drive to the store to get the other.

BT Whaler posted 04-02-2006 10:07 PM ET (US)     Profile for BT Whaler  Send Email to BT Whaler     
I have an old outrage. When I removed the drain tubes almost all of them looked like water may have leaked in. I'm thinking of increasing all of them to 1.25" holes for two reasons. First, for better drainage and the other to better inspect for any water damage especially in the transom. Is there any drawback to this before I buy a flaring tool, now that I have a choice (thanks to Tom).
Does the 1.25" flare as well as the 1" tube?
ukuslayer posted 04-10-2006 02:52 AM ET (US)     Profile for ukuslayer  Send Email to ukuslayer     
I was wondering if you start with the straight tube from mcmaster how do you get the first flare? Do you flare both sides at once through the hull or do you flare one side first before inserting through the hull. I saw derf used a preflared tube in the begining of this post. Then everyone was talking about the tubing from mcmaster and it is sold in lengths with no flare. I have a couple of tubes that I need to replace and any info on that first flare will be greatly appreciated.

Aloha Sean

ukuslayer posted 04-10-2006 02:58 AM ET (US)     Profile for ukuslayer  Send Email to ukuslayer     
I saw Tom's comment on making the first flare but he was using his air tool. I will be using the manual tool so if anyone has info on that thanks.

Aloha Sean

Tom W Clark posted 04-10-2006 11:30 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

One of the great benefits of the pneumatic flaring tool is that it is very easy to flare just one end. I imagine the same could be done manually, but you would need to cut and prep a rough length of tubing and stand it on end on your work bench and then pound one of the flaring dies with hammer to start the flare.

Once you have one end pre-flared, you can install it with the flaring tool and both sides should cinch up nicely.

For $20-$25, you can just go buy an air hammer and play around with that technique too.

ukuslayer posted 04-10-2006 01:34 PM ET (US)     Profile for ukuslayer  Send Email to ukuslayer     

Thanks for the reply. I was thinking along those lines and just wanted to see if there was some technique that others were using.

Mahalo Sean

kamie posted 04-10-2006 07:01 PM ET (US)     Profile for kamie  Send Email to kamie     

I did exactly what Tom describes when I did my tubes last summer. Anneal one end, stick it on a block of wood, put the die into the end and wack with a hammer. It only takes a couple of tries and you get the force just so. The hard part is making sure you strike it level, don't want to curl one side more than another. Once that was done, back to the pan of water to anneal the other, non flared end. Then your ready for O rings,caulk and the final flare in the hull. If you get the tubes from McMaster you will have plenty to practice on.

BT Whaler posted 04-10-2006 09:14 PM ET (US)     Profile for BT Whaler  Send Email to BT Whaler     
If anyone is interested I found an inexpensive air hammer to use as a flaring tool. Look up
item # is 139273.
ukuslayer posted 04-10-2006 09:18 PM ET (US)     Profile for ukuslayer  Send Email to ukuslayer     

Thanks for the confirmation, That is what I was thinking would work. I really appreciate the helpful reply's. This post will make my project much easier as it is the first time I will be doing this type of project.

Mahalo Sean

HAPPYJIM posted 04-10-2006 09:39 PM ET (US)     Profile for HAPPYJIM  Send Email to HAPPYJIM     
Harbor Freight has an air hammer on sale for $8 that's 8 bucks.

jkweigand posted 04-11-2006 11:44 AM ET (US)     Profile for jkweigand  Send Email to jkweigand     
Sorry for this long response, I also have experience with the trailer-ball flaring technique. This is what I did...

I replaced the transom thru hulls. First I cut the brass tube to length (leaving 5/16 add'l on both sides). I then cut the inside end on a slight angle to mirror the angle of the transom. Once that was done, I filed/sanded the ends to eliminate all burrs. Then annealed the inside end first (cuz I then blocked it in place against the splash well when I flared the other end). I set the trailer ball on the tubing (inside end) and hit it with pretty good force with a 5lb sledge. It took a couple good wacks to start the flare. Sometimes I was off-center a bit so one side would flare, but not the other. A couple more whacks with ball 'n sledge seemed to fix that. I stopped using ball/sledge when the flare was, say 45degrees - not enough. So I then rolled an o-ring onto the tube up to the flared end and used a ball-peen hammer to gently round the flared end beyond 90 degrees to hold the oring in place. Be patient and the flare will end up pretty nice. Remove the oring and anneal the un-flared end. I then inserted the pre-flared end, oring and a liberal amount of 4200 in the transom hole, blocked it securely in place, applied 4200 to other end around the brass tube, rolled an oring on to tubing and fitted it tightly to the outside of transom. I'm now all set to whack the tubing with the ball 'n sledge, which I do. I have a helper hold all the blocking in place on the inside, just in case it wants to move. Again, I get the flare started - say to 45 degrees, and finish with ball-peen hammer. I also had an old tool with a rounded edge that I could set on the end of the flare and then hit the tool with the hammer to minimize the risk if striking the boat by accident. In the end, it was a good result - however, I must admit that one of my thru-hulls took me 4 tries to get it right (too short, bad flare, once the oring was pinched out of the flare... lots of trial 'n error).

I should also mention that on my 18 Outrage, I had the good fortune of having 1" thru hulls in bow locker and sump which I replaced using Tom Clark's air hammer (THANKS TOM!) which worked great. Then on the transom, I had one original 1.25 thru hull that I replace using the bolt 'n die technique (thanks again, Tom!). The other two on the transom were 1 3/8 cuz a prior owner replaced those 2 with plastic thru hulls. I went back to brass, and since air hammer and bolt/die weren't set up for 1 3/8, I had to use the trailer ball technique. Having used all three techniques, I'd have to say the bolt/die is the easiest and, in my case, I felt I got the best result... but the air hammer was a close 2nd. With the bolt/die, you do both ends at the same time, which was real easy on the transom 'cuz I could see both flares being done at the same time. That would not be possible on the sump and locker, and some have said there are slight angles in the longer thru hulls, so the air hammer may be the preferred tool in the end.

I've rambled way too long... but thanks to all on this great forum for the encouragment and assistance.

Jack Weigand

DeeVee posted 04-23-2006 11:12 PM ET (US)     Profile for DeeVee  Send Email to DeeVee     
Many thanks to Tom Clark for the use of his drain tube replacement tool kit. With the right tools, this is a pretty easy job. The hardest part of the job was getting the boat off of the trailer to have access to the two stern sump drains (the bunks are in the way), and that was more time consuming than difficult.

The first try at flaring, after annealing the brass, I ended up with a bulge inboard of the flare. I am not sure, but I attribute it to annealing a larger area of the brass tube than required.

The next try, I only annealed about 1/2", or as little of the end of the tube as I could. Also, slightly tipping the air hammer and rotating at the same time seemed to help the flare form.

After modifying my technique, all attempts were successful.
I feel a lot better knowing that all the tubes are in good shape.

Thanks again Tom,

Doug Vazquez
1989 22' Outrage

montauk steve posted 04-24-2006 03:48 PM ET (US)     Profile for montauk steve  Send Email to montauk steve     
NICE article.

I am looking to replace the transom drain now, since it drips. Do i need to remove the old one drain tube first to confirm the diameter of the thru hole?



montauk steve posted 04-24-2006 04:12 PM ET (US)     Profile for montauk steve  Send Email to montauk steve     
NICE article.

I am looking to replace the transom drain now, since it drips. Do i need to remove the old one drain tube first to confirm the diameter of the thru hole?



Tom W Clark posted 04-25-2006 11:23 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

You need not remove the drain tube to determine its size. The size should be apparent. Just measure it.

The only places Whaler used anything other than 1" drain tubes were some of the transom splashwell drains on some of the 18-25 foot models.

Tom W Clark posted 04-25-2006 11:32 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I'm glad the tube replacement went well for you.

In almost every case of using the air hammer, there is a slight "reverse bulge" below the flare. For the most party this has been beneficial as it helps the tube cinch tight against the fiberglass skin of the hull, but as you note, if the bulge is too large and occurs on the initial flare before installation through the hull, it can make the tube too large to fit.

I think your advice about trying to limit the annealing process to the end of the tubing is good. I will pay more attention to that the next time.

I too sort of tip or roll the air hammer around a bit to help control the flare as it is formed. By paying close attention, one can get the angle on the pre-flare just right using this technique.

I agree the bolt and wrench will work the best with the dies IF the tube is perpendicular the hull. The air hammer becomes especially useful in are that are hard to reach and where tubes exit the hull at an angle.

DeeVee posted 04-25-2006 09:31 PM ET (US)     Profile for DeeVee  Send Email to DeeVee     
montauk steve

I just used a pair of channel locks to carefully grasp the outside edge of the drain tube flare and crush the flare inward.

The only thing I did not like about this method was that if the channel locks slipped off the flare (and it will), the tool snapped shut really fast- it hurts the area of your hand in contact with the handles- really bad for a couple of seconds.

I tried grinding the flare off, which worked OK, but one slip and you have a gelcoat gouge. I immediately went back to the possible pain.

Doug Vazquez

duckman posted 10-26-2006 07:58 PM ET (US)     Profile for duckman  Send Email to duckman     
Great reading! I ordered the stuff that you all have mentioned ( 1 inch brass tubing, o rings, flanging tool) and have modified my air gun to Mr. Clark's specs. When the parts arrive I will give it a go. I have a 1987 Montauk I am restoring and the drain tube was bad (no water in foam). The Whaler dealer here will not attempt the repair. After reading your posts I checked my other boat and sure enough it has a bad drain tube. So I want to thank you all for the information. I would have been in trouble without it.
stefan posted 01-23-2007 10:12 PM ET (US)     Profile for stefan  Send Email to stefan     
ok, this info is great, but if ya 'all could make sure I got this right, I'd be most thankful.

I have 1982 18' outrage, and O-ring of hull drain tube (bow locker) is ripped, and I see a hole in the brass tube, not far from opening. Crap who knows how long it's been there, I don't want to even think of water issues. Boat has not been in water since I noticed this.

There was always a little water in the bilge, that couldn't be from that right?- there'd be a heck of alot of water in hull right?- UGH,

SO back to topic- I order replacement tube part #8950K832 from Mc Master that Tom Clark has in post- 3 feet will be plenty, might as well do all that correct? 1 1/4 diameter correct?- I think all 5 on the 18 are 1 inch length. Also order the flaring tool for the 1 1/4 from ship store that Tom also has in the post, then the Orings from Mcmaster (which ones?) as well. Also the 3M 4200.

that should be all I need right? plus prayers of dry foam when I pull out the locker thru hall saturday.. I'll let you know

thanks, Stef

Martino posted 01-24-2007 12:29 AM ET (US)     Profile for Martino  Send Email to Martino     
Don't know about your 18, but my 22' Revenge used all 1" tubes. You may want to measure them. The only other advice that I can add is that when free-forming the initial flare on the tubing, there is a problem with the tube belling-out just below the flare. I picked up a large flaring kit on Ebay that does 1" tubing. If you have this problem, you may be able to borrow one from a friend in plumbing. At any rate, when you lock the tubing down in the flaring die, you don't have that problem. Once you install it in the hull, flaring the other end is no problem, as the hull itself seems to support the tube wall sufficiently. I used Mr. Clark's method with the air powered tool. Got the same professional results he showed. Good luck!
MyOutrage posted 01-24-2007 08:48 AM ET (US)     Profile for MyOutrage  Send Email to MyOutrage     
Stefan, don't place your order w/ McMaster yet.

I believe that all drain tubes are 1" OD on an 18' Outrage with the exception of the 3 transom splash well tubes (which I know for a fact are 1 1/4" OD).

I have an '89 Outrage sitting in my garage... I'll check sizes tonight.

Peter posted 01-24-2007 09:52 AM ET (US)     Profile for Peter  Send Email to Peter     
The three transom drains are 1 1/4 inch. The bow and stern thru-hulls are 1 inch.
stefan posted 01-27-2007 01:06 PM ET (US)     Profile for stefan  Send Email to stefan     
ok, removed bow locker tube, and foam is damp, from hole in tube, and boat hasn't even been in the water for a good 2 i proceed w/ drying methods mentioned, or go ahead and replace tube.
I never noticed extra weight when loading, I'm hoping it's minimal .


stefan posted 02-07-2007 07:37 PM ET (US)     Profile for stefan  Send Email to stefan     

mcmaster carr is quick-impressed!
question- I got the 213 O-rings- I know they're for the 1 inch tubes,but I don't think they'll fit w/ the 1 1/4 inch transom tubes.

tom, any idea what # ring for the 1 1/4?



stefan posted 02-07-2007 07:54 PM ET (US)     Profile for stefan  Send Email to stefan     
based on how #213 for 1 inch tube was calculated
(15/16 ID x 1 3/16 OD)
it looks like best bet for the 1 1/4 tube, if i'm correct (which I never am) it's # 217 (1 3/16 ID x 1 7/16 OD)

is that correct?

hauptjm posted 03-06-2007 10:35 AM ET (US)     Profile for hauptjm    
Based on this thread alone, I replaced the two drain tubes in my Whaler this weekend. The entire process took less than 1 hour, with no assistance. I used the advice of annealing the unfinished end and had no cracks or problems. I used the manual tool (bolts, washers and flaring bit). The only deviation I took was not to completely roll the brass over the o-ring back to the fiberglass. My local Whaler dealer showed me a factory example (photo) that brought the brass roughly half way back to the gel coat.

Thanks so much for all of the experience and advice y'all provided. It was invaluable!

stevedallas28 posted 04-03-2007 11:53 PM ET (US)     Profile for stevedallas28  Send Email to stevedallas28     
Is there anyway to make your own flanging tool? I understand the all thread and some washers, but what would you use to make the flange in the brass?

Tom W Clark posted 04-04-2007 09:40 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

If you had a machinist's lathe, you could turn your own dies, but why? It's not like you will save any money. You can buy the flaring tool with two dies for about $30-$40.

Spray posted 04-04-2007 10:01 AM ET (US)     Profile for Spray  Send Email to Spray     
Folks, this is good information. Can anyone chime in definitively on how to determine if or when the thru hulls need to be replaced? I have a 1987 Montauk with no visable signs of degridation in the thru hulls. I dont want to mess with them if that are OK however the replacemnt process appears almost painless, and that is scarry!

Thanks in advance Spray

Martino posted 04-04-2007 02:05 PM ET (US)     Profile for Martino  Send Email to Martino     
IMHO, you have two [problems]--the thru-hull and the O-rings. Even if the thru-hull is OK, the O-rings may be rotted away. Hard to inspect those. If your thru-hulls are OK, and there is no obvious evidence of o-ring failure, I would be tempted to leave well enough alone.
stevedallas28 posted 04-04-2007 07:51 PM ET (US)     Profile for stevedallas28  Send Email to stevedallas28     

Just trying to save myself some money on a tool I hopefully will only use one time. Just trying to curb costs, but I know with any boat project that is hard.

I will probably end up buying one of the tools, but just wanted to see if anyone had used something else.

capedave posted 04-08-2007 01:55 AM ET (US)     Profile for capedave  Send Email to capedave     
Hello can some one help of the part # for the brass tubing and o'rings from McMaster. I cant seem to find the
8950K791 listed in the brass tubing listing or the dash 213 o'rings??

Thanks Dave

Tom W Clark posted 04-08-2007 12:02 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

Visit and enter the part number in the search box. You will find that part #8950K791 has been superseded by #8950K793. If you then click the "catalog page" link, you will be taken to a .pdf version of the McMaster-Carr catalog page on which the part is shown.

Because the McMaster-Carr web site uses frames, I cannot offer you a direct link, but search on "O-ring" and you will be offered a page that describes them. Pick out what material you want them to be made of and read about the differences of materials. I believe the original O-rings that Whaler used were neoprene. I use EPDM.

The "dash" number simply refers to sizes.

Tom W Clark posted 04-08-2007 12:07 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The small investment in the flaring tool need only be temporary. If you want to save money, sell the tool when you are done with it.

Alternatively, you can just borrow somebody else's You can borrow my kit if you like but only after Eric Bozza is done with it in a week or so.

Tom W Clark posted 04-08-2007 12:09 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

If the O-rings have degraded, it will be apparent. it is the exposed portion of them that deteriorates first thus it will be obvious if they need replacement.

After 20 or 30 years of use in a Whaler hull, most O-rings are due for replacement.

mikejana posted 06-09-2007 07:10 AM ET (US)     Profile for mikejana  Send Email to mikejana     
One of the most informative threads on the site. It helped me this week.
SuperiorWhaler posted 09-16-2007 06:20 PM ET (US)     Profile for SuperiorWhaler  Send Email to SuperiorWhaler     
I have started the first steps of thru hull replacements on my 1981 22 Revenge. The detailed description of tools and techniques at this post has been extremely helpful. My question deals with the thru hull from the bait well that runs into the splash well. I am trying to imagine how I could ever put a flange on the end in the splash well. The clearance is appx. 4" ?? I have read the threads (and printed) religously, but must be missing the technique for creating a flange in such an unaccesible area. I would appreciate your advice. Thanks
Martino posted 09-16-2007 07:16 PM ET (US)     Profile for Martino  Send Email to Martino     
I did the replacement on a 1979 22' Revenge. Different set-up?? By splashwell, are you talking about the well directly in front of the outboard? Mine only drained outside, through the transom. The fishbox in the floor drained through the bottom of the hull. Is your set-up different? After practicing the technique before starting on the actual boat, I had no problem with the replacement. Got superb results with the tools and procedures recommended.
SuperiorWhaler posted 09-16-2007 08:01 PM ET (US)     Profile for SuperiorWhaler  Send Email to SuperiorWhaler     
Yes, the well in front of the engine. (see link) I refer to it as the splashwell (although it may have another term?) On a 1981 Revenge 22, the baitwell has 2 thru hull drains, 1) on the bottom of the well that ports directly through hull and 2) a horizontal thru hull from the baitwell, into the splashwell (same thru hull brass flange configuration). However, at the bottom of the splashwell (where the thru hull is located) you have about 4" of clearance. Question do I get a flange started in that small area? ANy advice helpful.

wb04431 posted 09-24-2007 05:10 PM ET (US)     Profile for wb04431  Send Email to wb04431     
Derf and others, can you tell me the best lenght, beyond the hull, to cut the pipe? 1/4" or 3/16". I have the Boston Whaler O-Rings, just was unclear if it was 1/4" past the O-Rings or from the hull?

I have manual flange tool, not an air driven tool. I assume that I should be cutting the brass tube at the angle of the boat on both sides (foward and aft). Both angles were different, I plan on cutting 1/4" from the hull, as derf mentioned.

I know it has been awhile since the last post, but hopefully somebody will respond.

Thanks, Bill

Tom W Clark posted 09-25-2007 10:48 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

As I mention above, run the brass tubing at least 1/4" beyond the hull (1/8" beyond the O-ring) to get a good "roll" on the tubing well beyond 90 degrees of bend. You want the flare to capture and retain the O-ring with the flared end.

Tom W Clark posted 09-25-2007 10:51 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I specifically address your situation above in my description of doing this very drain tube in the same hull. You cannot use the air hammer in this situation but we had very good results using the all-thead and wedge shown in the photo linked to above.

SuperiorWhaler posted 09-25-2007 05:06 PM ET (US)     Profile for SuperiorWhaler  Send Email to SuperiorWhaler     
Thank you Tom, I did overlook your post dated 11-22-2005 12:19 AM ET (US). Very helpful.
capedave posted 09-27-2007 10:44 AM ET (US)     Profile for capedave  Send Email to capedave     
I have had very good luck in with just a couple of ball pean hammers. Work slow and it is easy to get a very nice finish and angle that some of the tubes require.
tbryan5 posted 09-27-2007 10:39 PM ET (US)     Profile for tbryan5    
I'm planning on tacking this job this Fall and am studying this thread as if it were the thru hull bible -- great info. The air gun seems to be the most sophisticated and best option, but I don't have a compressor, air gun or a way to cut down the die. The flaring tool sounds easy, but it has its limitations on the thru hulls with angled ends (which I think are most of them, right?). Capedave seems to have the poor-man's solution with the ball peen hammers, but I don't have a good understanding of that method. Capedave, or others, can you elaborate?
Martino posted 09-28-2007 07:09 AM ET (US)     Profile for Martino  Send Email to Martino     
My best advice no matter what method you use is to practice, practice, practice. I would take a piece of plywood, about a couple of feel square, and drill a 1/2 dozen 1" holes in it. Learn your skills there, rather than on the hull. The importance of the annealing can't be over emphasized. It will not work without it.
Henry posted 09-28-2007 11:30 AM ET (US)     Profile for Henry  Send Email to Henry     
I used all three methods on each thru hull. I flared the first end with the air hammer. After the tube was placed in the hull I used the flare tool for the other end. Then I finished off each flare with the ball peen hammer (repeated light taps all the way around the circumference of the tube allows you to round off each flare). Seems to have worked very well.
tbryan5 posted 09-28-2007 06:43 PM ET (US)     Profile for tbryan5    
Thanks. You've provided more great info.
wb04431 posted 10-05-2007 10:25 PM ET (US)     Profile for wb04431  Send Email to wb04431     
I have a 1967 Montauk, 16'7". I am replacing the lower (~18") drain tube from the center drain hole to the lower transom.

I am disappointed with the outcome of this process, even though I followed all the directions as best that I could. I cut the brass pipe at angles on both ends, added 1/4 of an inch to each end. I annealed the end of the brass. I lathed the flange tools so that they could flange at an angle. I cut wood wedges at the proper angle. I got 3/8 all thread and put on the o-rings. What was the result? The o-rings did not want to be on the brass, they popped off continuously. But I could deal with that. Unfortunately, the brass drain pipe did not flange at the ends (especially on the forward end of the brass pipe).

Instead, the pipe expanded and bulged outward on the INSIDE of the boat. It expanded inside the boat, mostly on the forward inside, about one inch inside (behind the gelcoat layer, into the foam). Worse, the brass drain pipe did not seal on the forward end (in the floor bilge drain area) and it was at that end that the pipe expanded and bulged into the foam. Now I must somehow cut the pipe out from the inside.

I am really disappointed at these direction, more a haphazard collection of instruction instead of a cohesive and tested approach. My obvious problem, I didn't practice enough (each brass drain tube blank is $30 each), but I need some help.

Does anybody have any suggestions at how to cut out the bulged brass drain tube, and what I did wrong to cause the tube not to flange but to bulge inside?


Tom W Clark posted 10-06-2007 10:48 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Bill did you pre-flare on end before inserting the tube into the hull? Or did you try to flare both ends at the same time? If the latter, you will have trouble as one flare will complete before the other.

Always pre-flare one end and verify that is as you want it before proceeding. Understand that even the pre-flare will continue to roll a bit when doing the other end.

When you anneal the brass tubing, try to heat only the very end of the tubing so that you do not soften up too much on the tubing's length.

Martino posted 10-06-2007 11:36 AM ET (US)     Profile for Martino  Send Email to Martino     
My two cents here is that I had trouble putting a decent flare on the one end of tube prior to installation. Everytime I tried the tube would bulge just behind the point of the flare. I tried eveything. I ended up with a plumber's flaring kit. Lock the tube in the flaring block, flare it anyway you want, take it out, no more bulge. I then found that when installed, I could flare the other end in the boat with no issue, as the hull seemed to keep the tube's shape intact while I flared the final end. I put fairly large flares on the ones I did because I did not want to deal with the O-ring issue. One last thought, I tried the red silicone O-rings. Couldn't keep those rascals in place worth a dang. I had to go back with the black ones. A flaring kit that will do 1" tubing is expensive, even on Ebay. See if you can borrow one from a friend in plumbing. The process is very frustrating and annoying, until you get the hang of it. Then its moderately frustrating and annoying. On a scale of 1 to 10, I ended up with five nines, and one eight. Not bad considering the B/W dealer here had no idea what I was talking about when I inquired about them replacing the tubes. Good luck with it.
SuperiorWhaler posted 10-06-2007 04:08 PM ET (US)     Profile for SuperiorWhaler  Send Email to SuperiorWhaler     
Martino - I just completed the removal of all brass tubes from my 1981 Revenge 22. Happy to say I found basically dry foam (keel area had some dampness), but will let the hull dy over winter (heated/indoors).

I read your plumbers flaring kit comment and did some research, but find 7/8" dia. tools hard to find.
1) What is the brand name flaring kit you used?
2) what size flare did you use? (I believe I have all 7/8" dia tubes.


Tom W Clark posted 10-06-2007 04:20 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

The drain tubes in your 1981 Revenge are 1" not 7/8".

I have done dozens of drain tubes now. At least a couple I have had to do over because they were not so great. I have used the flaring tool as is, my power flaring tool and the ball peen hammers.

All these techniques will work well with different amounts of effort and skill required depending on the situation. I would not characterize any drain tube replacement as "difficult" and would not discourage anybody form attempting it at least once or twice.


There is no reason to pay $30 for 18" of brass tubing. Just order a length from McMaster-Carr or some other supplier. A three foot length cost less than $20 and you get two pieces or less than $10 each.

Once you get you unsatisfactory drain tube out, you will be able to cut it down and make shorter drain tubes out of it, so eve that is not a total loss.

To remove a drain tube, I like to collapse the flared end in o itself thus compressing it to less that the diameter of the hole in the hull. It will then slide right out.

Martino posted 10-07-2007 01:06 AM ET (US)     Profile for Martino  Send Email to Martino     
Tubing on my Revenge 22 was 1". I used an Imperial Eastman model 537 tubing flare set. It does large size tubing. New they are very expensive, I got a deal on a used one on Ebay. I figure when I am done with it, it can go back on Ebay!
wb04431 posted 10-09-2007 11:14 AM ET (US)     Profile for wb04431  Send Email to wb04431     
Tom W Clark,

I did not pre-flare (didn't know). Could you explain the pre-flaring process, using a flaring tool on all-thread on how to accomplish this (on angled brass tubes). Do I need a jig with the exact same dimensions as the boat to do this?

After you pre-flare the inside end, do you still use the flare tool on the inside flare when compressing the other flare? Can you go into more detail on pre-flaring and the procedure for a installing a pre-flared tube with angles on both ends and flaring the other end?

Annealing: I pointed propane torch at the ends, waited till it looked dark red and then turned the tube to get the other side (same end) then I did the other end. It annealed at the ends, but I am guessing it annealed up to 1" or 1.5" from both ends because heat travels easy on brass.

As for cutting it out, it won't slide out after cutting and compressing and mangling the flared end. The bulge is nearly a 1/16 of an inch and I need to cut the tube and compress it while inside the boat (where the foam is). Still struggling with this. The old tube pulled out after compressing the old flares, this one has bulged just a bit too much to slide out the current gel coat holes.


I used the black rings, and right now only one is still on. The other refused to stay on because it was so tight, and the 13 degree angle was too much tension to stay on. I want to try and find a more elastic o-ring that is made for this purpose. Maybe we have to pre-stretch these before rolling them on an angle.

I look forward to find the answer as to what brand of flaring tool and flaring block you used, that might help me pre-flare the inside flare and then only have to do the transom side flare on the boat. Does your tool work on angles for the flares (on both sides)? Does it need lathing to make it work on angles?

Thanks, Bill

SpongeBob posted 10-09-2007 08:59 PM ET (US)     Profile for SpongeBob  Send Email to SpongeBob     
Martino your email dosen't work. What kind of deal can I get on that flaring tool before it goes on ebay? Email me, I'm in Bradenton.


Tom W Clark posted 10-10-2007 01:32 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

This thread is getting too long. I fear I am now repeating myself.

I used my air hammer to create the preflare. I hold the length of brass tube in one hand and the air hammer in the other. It takes just seconds to create a flare.

I suggest you try using less heat or time to anneal the brass. Heat it until it begins turns blue but nor glowing red hot. Hold the torch so the flame shoots across and away from the end of the tube so heat is less likely to travel along its length.

A note or two on modifying the flaring dies: I do not own a lathe. I did not use a lathe to modify my dies. I shortened them with my cutoff saw. You could use a hacksaw on the die if it were clamped in a bench vise. You can use a Sawzall or you could use a grinder of even a Dremel tool with a small cut-off wheel. In fact that is how I cut my 1-1/4" die and created the groove for the E-clip that retains the dies on the air hammer mandrel.

To be really fancy, you can chuck a die into a drill press an set it to spinning and then cut it down. The cut will be very clean and uniform.

I tapered my 1" die with a belt sander and a regular old wood sanding belt, 100 grit. I just used what I had at hand. I suggest others be resourceful and do likewise. There is nothing particularly high-tech about any of this, it just requires some confidence and patience.

jrr posted 10-16-2007 01:58 AM ET (US)     Profile for jrr  Send Email to jrr     
I used my propane fish cooker to heat one end to a bluish purple, quenched it in water and formed that end. Placed it in the hull and measured 1/4" past the hull. Cut the tube, annealed it as above, put it back in the boat a formed the final flare. Worked like a charm. I used a ball peen hammer for one side, and a trailer ball for the other. Don't forget your gloves when annealing, brass transfer heat really well!
capedave posted 11-26-2007 07:19 AM ET (US)     Profile for capedave  Send Email to capedave     
I have found that the preformed end will continue to flair sometimes, I then back up that side with a wooden block on the end grain witch deforms enough to let the end I want to flair. FYI this is a lot easier with two people.
jhoward987 posted 11-26-2007 07:25 PM ET (US)     Profile for jhoward987  Send Email to jhoward987     
Thanks for the help!

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