1996 MONTAUK 17: Leak at cockpit sump drain

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
MattFL
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1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sat Apr 17, 2021 7:12 pm

In my 1996 Montauk [17] I just discovered a leak around the [cockpit sump overboard] drain tube.

Q1: How bad will the damage be if the boat is used for one more day before fixing the leak?

The cockpit sump would be full of water all day.

Q2: How well is the [foam] area around the drain tube inside the hull protected from soaking up water that might leak past the drain tube?

Q3: is it [perhaps means the area inside the hull near the drain tube] glassed off?

Q4: Or is it [perhaps means the drain tube] right up against the foam?

My main fear is water getting into the foam and rotting the transom.

I discovered [the leak in the drain tube] by cleaning out the sump while installing a new sump pump. Every time I wiped the sump dry, more water would come out from around the drain tube.

The hull was entirely dry for a few months so the leak must have just started after I dumped a bunch of water [into the sump] to test the new pump, then some water sat in it overnight.

This drain tube was installed eight years ago in 2013.

Q5: Is it likely the foam is soaking up this water?

Q6: Is the drain tube area glassed to be separate from the foam?

drain.jpg
Figure 1. Water is seeping from around the lower part of the drain tube after being wiped dry.
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Phil T
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Re: Drain tube leak, OK to use temporarily?

Postby Phil T » Sat Apr 17, 2021 7:21 pm

Sorry, don't use the boat.

Remove the drain and all the sealant.

Inspect the hole for rot.

Use paper towels to wick as much moisture as possible.

Use a hairdryer on low for a day to dry it out.

Coat the walls of the hole with marine sealant (Boat Life) not adhesive.

Install new drain with sealant. Use the threaded type, not the snap in.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Sat Apr 17, 2021 8:22 pm

It is much easier to stop more water from getting into the hull foam than it is to get water out of the hull foam.

When a drain tube passes through the Unibond hull of a Boston Whaler boat, the hole it passes through was probably not treated with any sort of sealant at the factory in the original fabrication.

The drain tube seen in Figure 1 does not look like the usual flared brass tube. The inference is someone replaced the original drain. Exactly what was done at that time with regard to use of any sealant for the foam in the interior of the Unibond hull is impossible for me to know. The only person who would know is the person who installed that drain tube.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sat Apr 17, 2021 8:29 pm

Ok thanks.

Q7: where can a replacement [drain] of the best quality be found?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Sat Apr 17, 2021 9:01 pm

MattFl wrote:Q7: where can a replacement [drain] of the best quality be found?


Matt - Sue Lodel, Parts Manager: http://www.beacontcm.com

You can't go wrong with Sue.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sun Apr 18, 2021 9:12 am

Great thanks. All of the through-hull fittings on this 1996 MONTAUK 17 are plastic. I bought the boat in 2000, and I believe the through-hull fittings were originals.

I replaced this particular through-hull fitting myself in 2013 with the part coming from [Twin Cities Marine].

I don't remember what was inside the hull, but I do remember using a ton of 3M5200 in hopes that it would never have to be replaced again--that's going to be fun to remove.

Q8: Is there a brass tube drain alternative that I should ask for?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Sun Apr 18, 2021 9:38 am

Given you used 3M5200 adhesive, you will probably end up destroying the drain tube when you try to remove it.

While earlier year models had brass drain tubes, I don't remember the year they changed over.

Brass tube install takes a bit more work and technique.

Q9: Can you see visually if the fitting is broken or cracked?

Q10: Where is the water coming from?

Q11: Loose fit?

If it is from above reasons, I would go back to brass, assuming the hole diameter is not damaged or enlarged.

Sue can get you the tube, O-rings and flaring tool. You will need a propane torch (not MAP) to anneal the brass and a metal cutting tool, e.g.hacksaw, to cut the tube to length.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sun Apr 18, 2021 11:45 am

As best I can tell, the leak occurs around the tube on the lower side of the drain.

The boat gets year round use. My guess is the constant in and out of the drain plug must have dislodged the gasket formed by the 5200 around the tube.

I'm handy but not a pro by a long shot. I think I should look for whatever solution has the best chance for success for someone who hasn't done this much.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Sun Apr 18, 2021 11:52 am

Using 3M5200 was probably a mistake. Removal may be difficult, as you already commented.

As I recall, there may be a solvent that helps loosen 3M5200. However, I have no idea what such a solvent might do to the foam in the interior of the Unibond hull. Proceed cautiously with any sort of solvent you might try to break the adhesion of the 3M5200.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Sun Apr 18, 2021 12:05 pm

That the c.1996 MONTAUK 17 had plastic through-hull drain fittings is quite interesting. I don't recall any mention of the change to plastic fittings from the brass tube fitting before in the MONTAUK models. That the drains are all plastic is new information. Perhaps Boston Whaler made that change to eliminate the need for skilled labor to install the brass tubes.

Q12: WIth the original plastic drain you removed in 2013, did you observe if there was sealant applied to the portion of the plastic tube that was in the foam passage through the hull?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sun Apr 18, 2021 2:13 pm

In all honesty I don't remember the condition of the original drain tube. From memory, I think there was some sort of sealant visible around the edges of the drain tube and it was deteriorating allowing the drain tube to become loose, which was why I replaced it. If I remember correctly. But I do not remember anything about what was inside the hull or how the drain tube came apart. I dug through some old pictures and this is the only one I saw with a clear view of the original drain tube, the picture is from 2003 and I cropped it to show just the drain area.

transomDrain.jpg
Fig. 2. Transom drain outboard end.
transomDrain.jpg (8.25 KiB) Viewed 5172 times


This does bring up another thought; the bilge pump tube that goes from inside the boat to inside the splash well; is there any way that could be leaking inside the hull? I wonder if the increased pressure from the new pump is actually pushing water into the foam area of the transom, and that water is trickling down inside the hull and running out around the lower drain tube?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Sun Apr 18, 2021 6:24 pm

Irregardless of what drain tube material, you can do one task that will prevent additional water intrusion.

After pulling the drain tube, dry the hole with a hair dryer so it is surface dry.

Coat the entire length of the hole with epoxy.

I would but 4 or 5 syringes of two part Locketite marine epoxy, mix together and use a tongue depressor or craft wood stick to slather it on the sides. Small craft brushes would also help in the application.

Once cured, reinstall the new drain tube.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sun Apr 18, 2021 6:40 pm

That's a great idea, I've got some West System epoxy in the garage, maybe that will do the trick.

Q13; what would be the best sealer to use on the drain tube?

I used 5200 thinking it would be the best and last the longest, hopefully forever, but that thinking was apparently flawed.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Sun Apr 18, 2021 7:04 pm

You want a sealant. 3M xx00 is an adhesive.

Look for Boat Life, Life caulk. It is a polysulfide based sealant.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Sun Apr 18, 2021 9:14 pm

I wonder what Whaler used to seal the plastic through hull fitting with the first time? Most have failed.

Plastic needs a compatible sealer. Read the labels.

If it were my boat I would consider putting the new plastic through hull together with West System G/Flex epoxy.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Mon Apr 19, 2021 9:46 am

3M advertises 5200 as an adhesive sealant and recommends it specifically for below the water line through-hull fittings, so on paper it should have worked, but clearly it failed for some reason. Maybe my surface prep was flawed?

https://www.3m.com/3M/en_US/company-us/all-3m-products/~/3M-Marine-Adhesive-Sealant-5200/?N=5002385+3293241623&preselect=3293786499&rt=rud

I'm going to order a new drain tube today and I'll definitely look into an alternative to 5200 for the sealer. If I remember correctly, the drain tube that is in there now is not threaded, it just slips together, and surely a threaded solution would work better, but I'm not sure where to find one. I'll ask Sue if they've got anything better than the one I bought last time.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Mon Apr 19, 2021 11:00 am

Q14: Will the 5200 bond to the plastic through hull?

Q15: What kind of plastic is the replacement Whaler through hull?

https://www.westmarine.com/WestAdvisor/How-to-Select-Sealants-and-Caulk


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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Mon Apr 19, 2021 11:32 am

Good question, I'm not sure of the answer but I'll ask Sue and see if she knows. I can see how that may have been part of the problem if the 5200 didn't stick well to that type of plastic.

Q16: what is the consensus on using a threaded stainless or bronze drain tube instead of the OEM plastic one?

I'm trying to remember if the OEM drain tube was strait or had a bend in it.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Mon Apr 19, 2021 1:48 pm

MattFL wrote:I've got some West System epoxy in the garage, maybe that will do the trick.
I would not have any doubts about WEST System epoxy for use in a marine environment. Boat assembled with WEST System epoxy 45-years ago are still held together by that product. In terms of a marine epoxy, there really is nothing particularly not-to-like about WEST System. I love the little foil package sizes. You can fixt a lot of problems with one batch from a foil packet or WEST System resin and hardener

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Mon Apr 19, 2021 5:09 pm

I emailed with Sue, she said the only metal replacement of the right diameter that she's aware of is the brass tube that you cut to length and install with o-rings using a flaring tool. I think I'll do my own search before ordering the OEM plastic one again.

Q17: what is the outside diameter of the drain tube?

I haven't removed mine yet for fear that it won't come out in one piece, leaving me with nothing to put back and the hull open to the rain.

Also I looked at it with my son and we've come to the conclusion that inserting and removing our expansion style drain plug must have flexed the plastic and weakened the seal over the years, leading to eventual failure.

I keep a quart of the West System epoxy and the little can of hardener around, it's great for the occasional odd job. If you use their pump system, one pump of resin gets 1 pump of hardener so it's really easy to measure out and mix. The hardener turned a dark brown after a few years in the garage, but still seems to work just fine.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Mon Apr 19, 2021 8:47 pm

If you go with the West System you need G/Flex to bond with plastic. The 105 does not bond plastic well.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Tue Apr 20, 2021 9:24 am

In regard to replacement on Boston Whaler boats of plastic through hull drains, Boston Whaler published a recorded presentation demonstrating their suggested method several years ago on youTube. See:

https://www.youtube.com/watch?v=Zby76eoKO-I&t=4s

From the ease that the original through-hull drain fitting is removed, the lack of installation with a strong adhesive like 3M5200 or 3M4200 is clearly evident.

Also the presentation demonstrates use of special tool used as a wrench for unthreading the coupling at the end of the fitting.

In the comments following the presentation, Boston Whaler mentions that the through-hull fitting and tool shown were made by ForeSpar.

There is also a comment (not from Boston Whaler) that the sealant is a product of SikaFlex. But that comment mentions a high-strength product, perhaps not appropriate, and might be best ignored.

I don't have any first-hand experience with SikaFlex products. They seem to be more oriented to OEM use rather than boat owner use, and may be harder to find. I recall that SikaFLex products have been mentioned with regard to use by Boston Whaler before in some discussions.

Tom Clark mentioned using SikaFlex 231 polyurethane caulk in a post several years ago in the old forum.

As for the difficulty in removing through-hull fittings that have been bedded with a strong adhesive, I relate my first-hand experience in a brief narrative I wrote after dealing with a reluctant fitting.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Tue Apr 20, 2021 2:55 pm

Thank you very much for the info. I don't think this particular drain tube has any indentations in it to fit a special tool, and it would be very difficult to access on the inside of the boat anyway. So this might be a fun one to remove. ;)

I have used Skiaflex products on my house, you can sometimes find them buried in the pro level stuff at Home Depot. They are very high end and work really well in that application, I would assume any marine products they make should be of similar quality.

I'm trying to find a threaded metal through hull, thinking it might hold up better to the repeated insertion and removal of the drain plug. What do you guys think about this style of through hull, assuming I can find one the right size:

temp.jpg
Fig. 3. A metal drain tube assembly, not the OEM nor the replacement part that will be used.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Tue Apr 20, 2021 4:37 pm

I think the metal through hulls are better. I could never find a size close enough to make work.

Q18: Isn’t the Montauk sump drain quite long?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Tue Apr 20, 2021 5:38 pm

Yes, I just measured it and it's right at 12" long.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Tue Apr 20, 2021 6:54 pm

Due to the slope of the transom and the sump wall, you will not get a good fit on the inside or outside.

This is why Boston Whaler used brass flared tubes. They can get a tight fit on the angles.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Don McIntyre - MI » Tue Apr 20, 2021 8:00 pm

I recall a conversation where there was mention of just that, a problem a problem with transom slope. The factory had various flare tools that were custom made according to the angle needed.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Don McIntyre - MI » Tue Apr 20, 2021 8:01 pm

Q19: Is the water coming from inside the drain tube, around the fitting?

Q20: Or from the cracking in the gel coat on the floor of the drain well that's observed in Figure 1?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Wed Apr 21, 2021 8:04 am

From memory, I think the plastic tube was not strait, I vaguely recall it had a little bend on one side. I will find out when the new one gets here (not removing the old one until the new one arrives so the hull isn't completely open to any rain).

As best I can tell, the water appears to be coming from under the bottom edge of the drain tube, around the flared part. Much above what appears to be a crack in the gel coat. I will study it carefully when I finally get it apart.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby conch » Sun Apr 25, 2021 9:43 am

Most likely [the leak is a result of] sealant failure.

If Twin Cities marine is sending a replacement part that is the same part as was originally installed, I would use that part.

Brass [drain] tubes went out of fashion [at Boston Whaler], and Peter Van Lancker made many changes [to Boston Whaler boats made under his leadership]. My 1992 and 1996 Boston Whaler boats do not have brass tubes--anywhere.

--Chuck

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Thu Apr 29, 2021 2:37 pm

Update: The new part arrived.

Sue said that 5200 was the thing to use for sealant.

To remove the old tube I first grabbed the flange outside the boat with channel lock pliers and gave it a twist to break the bond with the hull, at which time dark smelly thick water started running out. In total an estimated tablespoon or two came out.

Then I used a chisel to cut the flange off inside the boat and pulled the tube out the back of the boat. It all came out easier than expected. The whole tube was soaking wet.

As best I can tell, the seal on the back of the boat held up fine as no water was present there until I twisted it to break the seal, so either the leak on the sump side was the problem, or the bilge pump tube is leaking inside the boat and water running down--yikes.

Since water was dripping inside the sump, I'm crossing my fingers for that being the source of the leak.

I have no idea how much water the foam absorbed or how to get it out in a timely fashion.

More importantly, if the leak could have affected the wood in the transom.

A fan is drying now [the empty drain holw] while I contemplate the best way forward.

There remains a lot of cleaning and preparation to do.

Q21: does the embedded wood in the transom extend all the way to the drain tube area?

Q22: is there a chemical that I can soak the area inside the hole with to stave off any rot in the transom wood?

temp3.jpg
Fig. 4. View of the drain hole passage after existing drain fitting has been removed.
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temp2.jpg
Fig. 5. The old drain tube after removal and still wet.
temp2.jpg (89.82 KiB) Viewed 4933 times


temp.jpg
Fig. 6. The new replacement part for the drain as supplied from Boston Whaler dealer.
temp.jpg (44.39 KiB) Viewed 4933 times

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Thu Apr 29, 2021 6:34 pm

Looks like all foam to me from my easy chair.

Dry and clean up sounds right.

Tell us more about the bilge pump set up.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Thu Apr 29, 2021 9:28 pm

I poked around with my finger and everything inside there felt solid so maybe there's no wood to rot right there. When I clean it up I'll go back with a pick and double check. If it gets dry enough I might try to line the entire hole with 5200 before I put the new tube in, as a secondary tube in case it leaks again in the future.

Cockpit Sump Drain

temp.jpg
Fig. 7. The path of the cockpit sump drain pump exhaust has been routed through the forward bulkhead of the engine splash well, then the water is deflected downward by a partial cover over the outlet.
temp.jpg (97.55 KiB) Viewed 4839 times


The boat in Figure 7 is not my boat; my boat is [rigged] exactly the same.

The sump pump is down in the well. A rubber hose connects the pump to a rigid pipe that goes through [a bulkhead at the aft end of the cockpit] and exits into the engine splash well. The fitting that exits into the splash well is covered with a stainless steel deflector that diverts the water downward. It's the same exact effect as holding your thumb on the garden hose to spray the water down.

That flap creates some pressure, and if there is a leak anywhere around the pipe I could imagine it pushing water into the hull. That flap has never been removed so I'm not sure the condition of the sealer between the pipe and the hull. If that seal is falling apart then that could the source of a leak.

I may need to take apart that fitting and look in there.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Jefecinco » Fri Apr 30, 2021 9:39 am

Not to contradict the acknowledged expert but installing any part, especially any difficult to remove part that may need future replacement, with 3M 5200 adhesive may not be the best course of action. I believe a good sealant made for below the waterline use would be a better material for your application.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Phil T » Fri Apr 30, 2021 10:06 am

I would apply heat to the exposed hole for a day or two. A hair dryer on low heat would be effective.

After it is dry, I would coat the entire surface of the hole with sealant or epoxy. Let cure.

Install a brass tube with O rings and flared ends and not the abomination of PVC. Yikes.

Also - That bildge setup and fitting installed in the splashwell wall is cringeworthy. The idea is to avoid cutting through the skin into the foam.

Just run the discharge hose along with the steering cable and and add a 90 degree fitting after the drop in the transom wall pointing aft. It works.
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 1:50 pm

Re use of 3M5200: take advice to use that adhesive-sealant for this application with some caution.

I presume that the long assembly seen in Figure 6 is already assembled from three individual components and has been cemented together with a PVC cement. The long assembly appears to be intended to be put into place in the drain hole, then the second component, a sealing ring, will be installed onto the unfinished end once the assembly is in place in the hull.

Q23: Are you going to install the second sealing ring on the inboard end or the outboard end?

Q24: In Figure 5, is the black material seen on the old tube at the left end some sort of lubricant?

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 2:02 pm

MattFL wrote:Q21: does the embedded wood in the transom extend all the way to the drain tube area?

To learn where the hull has embedded wood you should contact Boston Whaler customer service and ask them to email a PDF document with the appropriate drawing. Generally the transom is reinforced with embedded materials, including some wood, only where needed. The area where an engine would be mounted will have embedded plywood reinforcement. Areas where other components will attach may have embedded reinforcements. Boston Whaler uses a variety of materials for embedded reinforcements, and not all are wood or plywood.

MattFL wrote:Q22: is there a chemical that I can soak the area inside the hole with to stave off any rot in the transom wood?

I don't have any first-hand experience with any chemical like that or any particular knowledge of them, but there is a product sold under the name Boat Life "Git"-Rot Penetrating Epoxy. You can learn more about that product from the manufacturer's website. See

https://www.boatlife.com/boatlife-blog/how-to/how-to-use-git-rot/

The instructions for how to use the product sound rather impossible to perform in real life.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 2:12 pm

[Moderator's note: this thread now contains 24 questions, and and seven illustrations. To facilitate discussion I have numbered all the questions and the illustrations. On long threads with many questions and multiple illustrations, giving identification numbers to them helps to be able to discuss them.]

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 2:24 pm

MattFl wrote:Q2: How well is the [foam] area around the drain tube inside the hull protected from soaking up water that might leak past the drain tube?

Q3: is it [perhaps means the area inside the hull near the drain tube] glassed off?

Q6: Is the drain tube area glassed to be separate from the foam?
I am not aware of any treatment applied to the foam after a hole was made for a drain tube during the boat fabrication at Boston Whaler. You should contact Boston Whaler customer service and ask them this questions, however the boat under discussion was made 25-years ago, and perhaps no one at Boston Whaler may be able to answer that question authoritatively.


MattFl wrote:Q4: Or is it [perhaps means the drain tube] right up against the foam?
I would anticipate that the diameter of the hole in the boat bulkhead for the drain is of a constant diameter throughout, with the hole diameter made just large enough to accommodate the outside diameter of the tube passing through the hole. Therefore the outside of the tube would be in very close contact with the foam.

MattFl wrote:Q5: Is it likely the foam is soaking up this water?
The foam used inside a Boston Whaler Unibond hull is know to retain water in some circumstances.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 2:35 pm

MattFL wrote:Q13; what would be the best sealer to use on the drain tube?

I can't offer any advice based on experience with this particular drain, but I would expect that the best sealant will be just that, a sealant, and not an adhesive that is trying to rigidly hold something in place. A sealant with some flexibility might be better for this situation where there could be some expansion or contraction of the drain tube or the boat itself, which might tend to break a rigidly adhered seal at one end or the other between the two parts.

MattFL
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Fri Apr 30, 2021 7:14 pm

It has been in the low 90's today and yesterday. With a fan blowing through [the open hole where the drain tube was removed] I hope [the foam] has dried.

I'm thinking the PVC part with the larger flanges might actually seal better than a thin O-ring due to more surface area. The tube gets a lot of abuse with the plug going in and out on every trip, and I think that might actually be what caused the problem, more on that below.

I agree on the bilge plumbing, and if I re-plumb it I'll use [another method].


jimh wrote:Q23: Are you going to install the second sealing ring on the inboard end or the outboard end?

Last time I put the ring on the inside [inboard] and this may have contributed to the premature failure. The plug is an expansion plug and has to go past that separate ring until it gets to the smaller tube to seal, and I think all that wrestling around with it compromised the seal over time. The ID of the flange that is already part of the tube is smaller, so I'm going to put that one inside [inboard] this time and see if it holds better.

jimh wrote:Q24: In Figure 5, is the black material seen on the old tube at the left end some sort of lubricant?

That dark brown stuff is some sort of biologic film. or mold. or something that grew from the moisture, or maybe some chemicals from the foam or glass that was washed out by the water. It smells bad. The smell reminds me of Florida swamp muck, the sweet rot kind of smell. Maybe fish gut water got into the hull through the leak and it's related to that.

MattFL wrote:Q4: Or is it [perhaps means the drain tube] right up against the foam?

Now that the old tube is out, I can definitively say that the hole in the foam is larger than the tube and is not touching the tube once the tube is installed. As I pulled the tube out it was rattling around loosely in the foam.

MattFL wrote:Q13; what would be the best sealer to use on the drain tube?
After watching some Boston Whaler recorded presentations replacing smaller through hulls on newer boats, I'm going to do what they did: use 3M5200 and a brush; try to paint the entire inside of the foam tunnel with 3M5200 to more or less make a skin on it; then I'll glue in the tube with 3M5200.

The 3M5200 is recommended specifically for through hulls, remains flexible, and Sue confirmed it was a good thing to use. This time I will be extra careful with my surface preparation. I'm also going to rough up the PVC parts with some 120 grit sandpaper, and then clean them really well to help with adhesion.

jimh
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Fri Apr 30, 2021 11:28 pm

MattFL wrote:After watching some Boston Whaler recorded presentations replacing smaller through hulls on newer boats, I'm going to do what they did: use 3M5200 and a brush; try to paint the entire inside of the foam tunnel with 3M5200 to more or less make a skin on itl then I'll glue in the tube with 3M5200.

Q25: what is the URL of the recorded presentation made by Boston Whaler that explicitly mentions using 3M5200 adhesive to bed the replacement drain tube in place and what time in the recording does that mention of 3M5200 occur?

MattFL
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Sat May 01, 2021 3:47 pm

In my post I didn't mean to imply that [Boston Whaler] were using 5200, more so that they were coating the entire inside of the hole with sealant to give it a skin. I can't tell what sealant they're using but here's the video showing their recommended procedure:

https://youtu.be/Zby76eoKO-I

jimh
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Sat May 01, 2021 4:59 pm

I have watched the presentation you now cite from Boston Whaler many times and I am completely aware that they never mention 3M5200. Also, I already mentioned that presentation and already gave a link to it.

Your earlier seemed to imply that Boston Whaler endorsed or recommended using 3M5200 in an on-line presentation demonstrating replacement of a through-hull plastic drain at the transom. I thought that inference was VERY unusual, which is why I asked for you to give the URL to the presentation(s) you were citing.

As you now observe, there was no explicit mention or endorsement of 3M5200 by Boston Whaler in the recorded presentation you watched--which is the same observation that I make from watching the same presentation. There are some comments contributed by random people who viewed the presentation that mention particular products, but I do not see any way to make an inference that Boston Whaler endorses any of those products mentioned in other people's comments.

Again, if there is any on-line recorded presentation or other information directly coming from Boston Whaler that demonstrates or recommends or endorses using 3M5200 adhesive sealant for bedding a plastic drain tube in place that passes through the hull at the waterline on the transom, I would be very interested in getting a URL to that information.

ConB
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby ConB » Sun May 02, 2021 6:48 pm

May be this Total Boat goop would be good.

https://www.totalboat.com/product/seal/

Con
!987 Outrage 18 / 1987 150 hp Johnson & 1969 13 / 30hp Johnson tiller

MattFL
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Mon May 03, 2021 10:43 am

ConB wrote:May be this Total Boat goop would be good.

https://www.totalboat.com/product/seal/
Thanks, that sealer looks interesting. I might have tried it if I wasn't already done.

I [installed the new drain tube] using 3M5200 FAST CURE. 3M5200 FAST CURE is slightly thicker and less runny than 3M5200, which actually made 3M5200 FAST CURE easier to work with. 3M5200 will run, but 3M5200 FAST CURE stays put much better. 3M5200 takes a week to fully cure and 3M5200 FAST CURE takes 24 to 48 hours, permitting plenty of working time.

In an effort to put a skin on the foam, a cut-down paint stirrer was used to reach inside and coat the ID of the drain hole.

I was very careful with surface preparation on this installation;
  • all old 3M5200 adhesive was removed;
  • every surface was roughed up with 120 grit sand paper including the surfaces on the new drain tube;
  • the ridges on the drain tube flange left over from the forming process were sanded flat;
  • the new plastic drain tube was washed thoroughly with dish soap to remove any oils and dust,
  • and the surfaces on the boat were cleaned with CRC Electronic Cleaner, which is excellent for removing oils and quickly dries to leave no residue.

The surface cleaner recommended by 3M was more than $20 a can--too expensive for this single use.

I hope [the newly installed cockpit sump drain] will [adhere to the hull] for more than seven years this time.

After careful consideration, I put in [the main portion of the new plastic drain tube] from [the transom inward toward the sump]. Then the small flange or ring was installed on the cockpit drain sump side.

The gap between the hole and the drain tube was rather large; the fit was pretty loose. This [method of installation] seemed to give the best fit.

temp.jpg
Fig. 8. Close-up view of misfit between the drain tube and the iboard flange. Alignment required bending the tube to meet the flange ID.
temp.jpg (37.27 KiB) Viewed 4327 times

As seen above, the flange [on the inboard end of the drain] is centered in the [existing drain hole]. Notice the misalignment between the flange and the tube. Best fit was achieved by inserting the tube the stern towards the interior, then reaching inside the flange with a finger and putting enough force on the tube to bend it into alignment with the flange. Then the pieces pressed together easily. Also, Inserting the tube from the outside of the boat was much easier [than if the new drain tube were inserted from the inboard side].

[The replacement drain tube] is in place. I hope this installation will be the last repair. If not, then I hope the decision to use 3M5200 wont [cause difficulty in removal of this tube to perform a third installation]. To remove the existing drain was not difficult.

To get the boat really cleaned up took perhaps two hour--and now I am going fishing

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby Jefecinco » Tue May 04, 2021 9:50 am

I certainly hope it is the last time. I'm sure the tube can be removed in the future without damage to the surrounding material if great care, skill and patience is employed.
Butch

MattFL
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby MattFL » Tue May 04, 2021 12:18 pm

I hope it's the last time, too.

The last [cockpit sump drain on this 1996 MONTAUK 17] was installed using 3M5200. To remove that drain tube was not difficult. I just grabbed the outside flange with channel-lock pliers, gave the tube a twist, and that was enough to break the bond.

There is a significant gap between the tube and the hull due to the size of the holes drilled at original manufacturing. I think that gap reduces the strength of the bond. The flange is larger than the hole, but not by much; the tube rattles around in the hole pretty loosely. It's definitely not a press-fit part.

jimh
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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Tue May 04, 2021 2:16 pm

With regard to the curved path that the original drain hole seems to take, perhaps that hole was made by drilling from each end, rather than making a single pass through the hull with one hole saw. Or, perhaps an initial smaller diameter pilot hole was drilled in one-pass. Then the larger diameter holes were drilled from each end until they meet. Other than that approach, I cannot see how a curved hole could be made with a hole saw--unless there was some sort of universal joint in the drive shaft between the hole saw and the drill motor.

I cannot see a particular motive to create a curved path hole for the straight drain tube to fit into. Boston Whaler workmanship on that day in 1996 when this hull was made might not have been at its finest quality level.

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Re: 1996 MONTAUK 17: Leak at cockpit sump drain

Postby jimh » Tue May 04, 2021 2:23 pm

With regard to the apparently poor adhesive bond that existed between the plastic drain components, the fiberglass laminates, and the interior foam in your prior installation that allowed such easy removal of the drain from the long hole through the hull: I am quite surprised that the bond between the plastic, the adhesive, and the hull was so weak. The general notion of the strength of 3M5200 adhesive suggests its bond would be much stronger than you describe in your narrative of the removal of the old drain tube. My own first-hand experience in attempting to remove a through-hull fitting that had been bedded in place with a strong adhesive sealant was very different from your experience in removing the old drain. We were hitting a plastic through-hull fitting with a large mallet, and it would not budge. There was not a chance we would have pulled it from the hull with slip-joint pliers. We had to cut into pieces and chisel it out.