Removing Water From Hull

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
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Removing Water From Hull

Postby dps616 » Wed Sep 21, 2016 10:28 am

I recently purchased a 1986 Boston Whaler SUPER SPORT 13 that looks to have about 200-lbs of water in the hull. The lower drain tube on my Boston Whaler 1986 SUPER SPORT 13 was leaking. I removed the drain tube to put in one that does not leak.

I saw a video where a Carolina Skiff owner did something interesting to remove water from his boat's hull: he drilled two holes in the stern and used an electrician's flexible drill bit to open up a channel in the wet foam into the hull about 6-feet from the stern. I have access to one of those bits and was thinking to try it. Does anyone have experience or opinion on this method?

Or, perhaps using a vacuum to draw moisture out.

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Re: Removing Water From Hull

Postby Eric801 » Sun Oct 09, 2016 9:12 pm

[Speculates that there] are lots of people who'd like to find out how to get water out of foam hulls--me, too.

[To remove water from boats with foam hulls] I have:

--drilled holes and drained: [no success];

--drilled holes and hot boxed to vaporise the water: some success;

--cut the hull exterior, cut out the foam and replaced: [success] but a huge job.

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Re: Removing Water From Hull

Postby Jefecinco » Mon Oct 10, 2016 9:43 am

Twenty-five gallons is a lot of water to have in any hull, much less a 13 foot hull. Where could all that water be located? How did you determine your hull has 200 pounds of water inside?

Carolina Skiffs are very different from Boston Whalers. The foam is likely to be different as well as the density and application method. I would not try the method described in the video. If I had a Sport 13 with 200 pounds of water in the hull I would try to sell it. I would then look for a much drier hull. I don't know if there are any classic hulls with no water in them but there are plenty with so little water that it does no harm. A little water is not a big deal.

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Re: Removing Water From Hull

Postby jimp » Mon Oct 10, 2016 5:25 pm

You can always wait...

295 pounds in 14 years. Maybe 35 gallons of water. But you probably want to use your boat sooner.


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Re: Removing Water From Hull

Postby Fisher18 » Wed Oct 12, 2016 9:45 am

I had a c.1979 hull that was waterlogged. I performed the procedure below in c.1995. The boat is still going today, 2016, with a new owner.


--drilled several holes low on the transom and some water ran out.

--then cut some 1-inch-holes in the deck. As I recall, two forward of the console and two aft.

--then pressurized the hull with a shop vacuum by reversing the air flow and duct taping the nozzle to the holes, one at a time. The boat was tipped up about 45-degrees. When I started the vacuum, water ran out of the hull for about 10 hours.

--repeated the process over several days and eventually got to the point where nothing came out

--continued the process for a few more days to "dry" the inner hull.

Unconventional? Yes, however, it seemed to work.

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Re: Removing Water From Hull

Postby dg22 » Wed Oct 12, 2016 12:22 pm

I would just be cautious about how much air pressure you force into the hull. You don't want to delaminate the fiberglass from the foam by doing so. I would let gravity do the trick and simply tilt the front of the trailer up so the water drains to the rear holes.

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Re: Removing Water From Hull

Postby dps616 » Fri Oct 14, 2016 10:19 am

Good morning and thank you to everyone who replied.
I came up with the 200 lbs. of water by:
--13’ super sport = 400
--Trailer ~ 400
--Motor = 160
--Battery and gas = 40
--Total = 1000 lbs.

I had all it weighed on a certified scale at 1,200 lbs.

Based on another post, I put in three deck inspection plates: one in front of the console where only the lower portion of the foam was wet; two behind the aft seat where the foam was fully wet.

Also, I did go ahead and run the long drill in two places from the stern, forward, in the hopes that if I applied shop vacuum [suction] the water would run out.

I plan to install garboard plugs in the two holes that can be open anytime the boat is not in the water to drain the foam water.

However, I have had very little water come out even with the hull tilted up for weeks. As someone else said the foam is tenacious in holding the water.

The boat gets up plane well, and is not pooped by the following wave when slowed down since there is a stingray fin on the 40 hp outboard. However, I want to get out as much water as possible.

DPS616 – 1986 13’ super sport with 40hp Yamaha

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Re: Removing Water From Hull

Postby dps616 » Fri Oct 14, 2016 11:21 am

Two more thoughts:

It looks like most of the water came in through the lower drain tube. The O-rings were gone and damage to the ends of the tube allowed water in. People may want to keep an eye on their drain tubes.
I will replace mine with brass flanges on the ends with a schedule 80 PVC pipe between that will be sealed with caulk.

I am anecdotally checking the water amount by lifting the hull on both sides near the stern and near the console. Since I have been trying to get the water out it seems that the water is moving around. The port side appears to be lighter and the starboard has gotten heavier.

1986 13’ super sport with 40hp Yamaha