Remedy for Compromised Hull Drain

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Dlincon
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Remedy for Compromised Hull Drain

Postby Dlincon » Wed Dec 07, 2022 3:07 pm

I have a restored 13-footer that had been out of the water for several years. I'm reasonably confident the hull was as dry as a 1972 hull could be. Recently the boat sat in saltwater for ten days. When I towed the boat home, I realized the main drain tube was compromised. I am sure saltwater has gotten into the hull.

Q1: [should I make a] repair [to] the drain tube and not worry about [water ingress]?

Q2: [should I] drill two holes and see if any [saltwater] drains out?

I can't see there could be a lot [of water] that would come out by draining [through two new holes in the hull]. I think that once water gets into [the interior foam of the Unibond hull] it is not coming out without significant work.

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Phil T
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Re: Remedy for Compromised Hull Drain

Postby Phil T » Wed Dec 07, 2022 4:47 pm

Q1: [should I make a] repair [to] the drain tube and not worry about [water ingress]?
Air dry the drain hole using a hair dryer. Coat with marine sealant (Life Caulk) and install new tube.

Q2: [should I] drill two holes and see if any [saltwater] drains out?
Don't bother making more to fix. Drilling rarely works.

I think that once water gets into [the interior foam of the Unibond hull] it is not coming out without significant work.
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jimh
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Re: Remedy for Compromised Hull Drain

Postby jimh » Thu Dec 08, 2022 6:46 am

Remove the compromised brass through-hull drain. Examine the foam for evidence of retained water. Let the drain hole dry. You can accelerate the drying by blowing warm air into the drain passage. The drain hole should dry out in a few days. Install a new brass through-hull drain. See the FAQ for advice at

Q12: How Are brass drain tubes replaced?
https://continuouswave.com/whaler/reference/FAQ/#Q12

Dlincon
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Re: Remedy for Compromised Hull Drain

Postby Dlincon » Thu Dec 08, 2022 7:53 pm

Both upper and lower drain tubes [are now] removed. [The] lower [drain tube was found to be] crumbled for at least four inches and was definitely compromised. [The] upper [drain tube condition] was better but [that drain tube was also] compromised.

[I have been using a] shop vacuum [to suck or blow air] through the hole. Moisture [is definitely present]. but [the exposed foam is] not what I would call "wet." [The condition of the exposed hull foam is] more like "damp." After four hours of moving air [through the drain passages] they have dried out considerably. I plan to continue to run air through the drain holes continuously until the copper tube arrives.

At this point I am not worried about [the foam being saturated with water].

jimh
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Re: Remedy for Compromised Hull Drain

Postby jimh » Fri Dec 09, 2022 8:47 am

Dlincon wrote:Both upper and lower drain tubes....
I don't understand your reference to multiple tubes in locations "upper" and "lower." Are you describing two different hull drains in two different locations on the hull?

Dlincon wrote:I plan to continue to run air through the drain holes continuously until the copper tube arrives.
The drain tubes are made of brass, not copper.

Dlincon
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Re: Remedy for Compromised Hull Drain

Postby Dlincon » Fri Dec 09, 2022 9:14 am

Yes - mistake on the brass versus copper [material for the drain tubes].

There is the drain for the well and a drain for the floor. Both tubes were compromised. Both being replaced.

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Re: Remedy for Compromised Hull Drain

Postby jimh » Sat Dec 10, 2022 9:55 am

Dlincon wrote:There is the drain for the well and a drain for the floor.


The drain "for the well" is referred to as the engine splash well drain.

The drain "for the floor (sic)" is referred to as the aft cockpit deck sump drain.

In nautical terminology the definition of "floor" is as follows:

    floor
    The transverse structural timbers to which the longitudinal bottom planking is attached. The equivalent side timbers are called the frames. The keelson is fastened on top of the floors, bolting them to the keel. The planking is the exterior of the hull, while the ceiling is attached on top of the floors, and it forms the base of the hold.