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Author Topic:   Drain Tube replacement
LarrySherman posted 07-27-2001 11:17 PM ET (US)   Profile for LarrySherman   Send Email to LarrySherman  
While working on the boat today, I decided to give my drain tubes a very close inspection, somewhat prompted by the "are we kidding ourselves" discussion in the general section. Most of them look and feel ok, but yes, I did find a problem.

The forward tube in the forward baitwell/sump on my 25 had some white residue around the edge of the tube. I felt inside it, and it felt ok. I probed around the tube with an awl, and it didn't sound right.

Well, the guy who built my stainless bow rail messed up (note the lack of expelitives, when they would be soooo useful here!), and made it 10" all around, instead of 18" at the bow, going down to 10" as I asked him. so I thought "Well, it will take him at least another month to get it built the right way, and I've really missed the season already, so why not begin next years refit now?"

So I took my screw driver and hammer, and began a striking. In about 15 min, I had a severly mangled brass tube in my hand, with an obvious corrosion hole in it. The foam, a nice nasty brown color, was definatly moist. No running water at least!

A few observations, and then some questions.

1) Could this design be any cheesier? I mean really, for a supposed top dollar boat, there could have been a little more ingunity applied here.
2) I don't see how any whaler afloat would not have moisture, and perhaps water, in the foam with this design, especially if the boat is kept at the dock.
3) There is very little in the way of a sealing surface, essentially, just an O ring and a small amount of caulk.

Now, the questions.

I want to improve on this stae of affiars, and would really like to hear what others have done. I went out and bought a few different 1" od thru-hulls, to evaluate the possibility of using them.

1) A bronze threaded thru-hull, with a 2 1/4 inch flange withe an exelent bedding surface. I could only use it in 6 of the 8 (8!, isn't that a few too many on a 25 foot boat!) thru-hulls. The port and starboard bait wells being the exception, because of the moulding of the hull liner.

2) a Forespar plastic thru-hull. Very nice, well built, but not quite long enough, plus, has ridges inside tube which would prevent any type of plug from being used.

3) A variety of brass drain tubes. I found 3 different kinds, all just long enough, each with a slightly different flare. I like the west marine one best, I would hold an O ring very well, due to the nice round-over of the flange.

I tried to find nylon drain tubes thet were long enough, but failed. I think Bigshot mentioned that they were availiable, can you tell me where?

Also, each of the thru-hulls was/is covered with a clam-shell ventilator plate, with 5 screws. I could not find anything like it, and I spent hours looking through mfg catalouges at the different marine supply stores I visited today.

Thanks in advance for the help, Larry

Makonut posted 07-27-2001 11:51 PM ET (US)     Profile for Makonut  Send Email to Makonut     
Here ya go Larry...try this:
LarrySherman posted 07-28-2001 12:06 AM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
Thanks Makonut, at least I know these would be the right ones. I sent them an email asking for a picture, and if they had any made of nylon.

Reading through the old posts, it seems that others have used bronze threaded thru-hulls as well. there is a thred in which bigz talks outrage and outraged through some of the steps. If you guys are out there, can you let me know your thoughts please?

Thanks, Larry

bigz posted 07-28-2001 07:33 AM ET (US)     Profile for bigz    
Larry S, there are other post on this topic than just the one you came across, to bad we don't have a search engine for topic and thread ;}!

Ok once again here is what I have done and learned about these miserable drain tubes!

These are one of those items which on any boat not just Whaler that sits in the water most of the year or all year must be annually checked. Water equalizes up the tube compressing the air above and consequently over time the area where it stops will rot in either fresh or salt. Trailed boats aren't as much of an issue.

The bronze is the safest way to replace, one important point though, since the area is on an "angled" section of hull the mushroom flange will have to be set in an epoxy fiberglass bedding compound (epoxy mixed with chopped fiberglass strands) to get a solid seal then the tube will go straight into the bilge's and fish boxes-- Using the brass tubes which are flared addresses this issue since they are soft metal and would conform.

You do not want nylon or plastic flanged thru hulls below the water line period. Might add if one uses these unwittingly the same bedding on the outside of the hull as mentioned above must be done, caulking will not work.

On the inside seal it with Boat Life or 3M 4200 under the flanged nut, use a brass/rubber plug the type that has the T-handle to tighten, or as I have done the stainless style ones (light coat of Vaseline on the rubber).

Mr. VanL got smart with the 27WA had it designed as a bottom stern bronze garboard drain installed just above the keel, which has the plug on the outside, can easily be removed, unlike the older 27's which like the other smaller "bigger"ones that had it down in a some what an inaccessible bilge depending on the configuration through the bottom. This used a combination on the 27's of the dang brass tube and a plastic garboard plug which the tube was inserted into the brass tube on the inside -- The others just used a brass tube with a plug.

The reason I mention this, it would be almost as easy to do this retrofit on your 25! Have the old stern bilge hole filled and glassed and install a bronze or in this case could use a "nylon" or "plastic" garboard drain through the stern into the low spot of the bilge, with the plug on the outside. Just a thought. If you opt for this method you might want to enlist the help of a professional, unless you are confident you can get the hole patched properly and smoothed to the hull --- then properly drill the stern hole so that the new drain will fit and seal.

LarrySherman posted 07-28-2001 08:29 AM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
bigz (tom, right?),

Thanks for the post, you are the man I was hoping to hear from. I did read your thread on this some time back, but I still had some questions:

When bedding the bronze thru-hull in the epoxy and chopped fibers, do I set it wet and leave it, or set it to shape then epoxy base, perhaps with some wax on the bronze, then pull it off when dry, and re-bed it in 4200? I'm thinking the latter would be better, but am not sure.

Were the clam-shell ventilators orgional equipemnt on Outrages? I've looked through tons of posts, but have not seen them mentioned. It would seem that without them, water would be constantly shooting up through the drain tube at speed.

What method do you use to close the bronze thru-hull? A smaller diameter plug? A valve?

As for the transom, I'm going to rebuild it this winter, and will make the change then. It sounds like a good idea.

Thanks again, Larry

bigz posted 07-28-2001 10:38 AM ET (US)     Profile for bigz    

You have to sand and sort of gouge the hull slightly around the mushroom area, your only talking a factional offset here, you need good surface adherence for the epoxy compound. I might add that this was used for the aft bilge drain tube, and we didn't use it for the fish tank drain tubes but certainly could have --- these were still solid on the '87 with the clam shells in place creating a venture (sp) effect to drain the water while underway.

The technique we used was to gunk up the mushroom flange with compound (sort of butter the hole area and exposed foam not load it with compound) , then ease it up the hole and before it set caulk the inside flanged screwed it down sung, note don't tighten it down like your tightening up a wheel lug just nice and snug so that it feels like it has good contact with the surface and most of the caulk has squeezed out. Then immediately clean all excess epoxy from around the mushroom --- make sure it is all filled.

Now you could use your idea using wax paper or release agent around the mushroom head then force it slightly into the epoxy compound and snug'n up the inside nut, after setting remove it, then bed the outside and inside with say 4200 --- would be removable --- using the heavy bronze though probably out last the hull -- in our case never wanted to fool with that bilge drain again a real "bitch" to get into from topside!

I will be replacing the two fish box drains on the 27WA this Fall or early Spring with bronze only area thankfully they used brass tubes (note these fish boxes don't use clam shells they are drained using a macerator pump, filled by using the saltwater wash down) --

Plugs, use a smaller diameter, believe the org. 1" you can get 3/4" that when tight will plug almost 7/8" or if necessary 1/2" which when tightened up will plug almost 3/4", a 1" when tight can actually handle close to 1-1/4 hole nice and snug. If your using the interior threaded thru hulls could just use a standard threaded square head pipe nut, you really want to be able to remove them easily so use a plug.

Hope this helps,time consuming but relatively easy so have fun and good luck!! Tom

LarrySherman posted 07-31-2001 05:44 PM ET (US)     Profile for LarrySherman  Send Email to LarrySherman     
Chuck sent me this info. Does anyone have an opinion (sp?) as to the quality and design of the new plastic drain tubes?

The brass thru-hull drains could be replaced with new brass drains (part #
1042894 for a drain that is 15" long and pre-flared on one end) and rubber
o-rings (part# for each side), or the newer style plastic
thru-hulls (part # 1042084 for a 5" drain tube and part# 1042068 for the
snap nut that goes on the other side of the tube).

The old holes would have to be enlarged to 1 3/8" to accommodate the newer
style drains and the newer drain tubes should always be installed from the
outside of the hull with the drain nuts on the inside. Use a Bostik 920 or
3M4200 to seal it at either end.

The original clamshells should have been chrome plated bronze with 5 holes,
however, Whaler has been using the 3 hole versions, probably from the mid
80's on, including todays models.
The part # for the Perko 2 X 2 chrome plated bronze clamshells is 533430.

Any of these parts can be ordered through your local Boston Whaler Dealer,
most will have them in stock.

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