Finding a hull leak

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Finding a hull leak

Postby NHSteve » Tue Apr 09, 2019 5:58 pm

Hi Folks
I bought what I think is a DS1 last summer and had a bunch of fun lake sailing. The hull number is 22629. I see some fiberglass damage at the corners of both seats where they meet the hull. The seats are pushed up so perhaps this is damage from trailering?

Water weeps from the cracks on the port side seat and I would like to know where it is coming in. Last weekend I pulled the drain plug out of the port side seat and filled the hull up with water to a level at least 2" above the seat cracks. I expected to see some drips coming from the hull to let me know where the hull leak is but instead I got nothing.

After bailing the boat out I put a half gallon of water in the seat and saw it run right out of the crack so I know this is the water path.

Any thoughts on how to find this hull leak?
NHSteve
 
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Joined: Tue Apr 09, 2019 5:09 pm

Re: Finding a hull leak

Postby GreenLake » Tue Apr 09, 2019 9:25 pm

Welcome to the forum!

Your DS should be pre 1971 and has the single hull with separate seat tanks glued on. Normally those seat tanks were filled with styrofoam blocks (the old kind, not what they use for builders foam now). That foam tends to get waterlogged. Even if it wasn't, your experiments would have made it so. Unless some previous owner removed the foam, you'll need to replace it (with pool noodles for example). You'll find descriptions for that process either here or in the DS1 section of the forum, like this recent post on foam removal.

The standard method for finding leaks works like you described, except adding food coloring 8) for better visibility, but I tend to doubt that you will find any leaks this way. Your implied assumption is that the leak in the hull is close to or below the waterline in an area covered by the seat tank. Unless there's a visible crack in the hull on the outside, I'm not encouraged that you'll ever find anything there. You don't report such visible cracks.

If my boat had a crack between seat an hull, it would easily be possible for water to get inside the seat tank from the cockpit during sailing, and then to weep out afterwards. Sources of water in the cockpit include a dripping seal on the CB handle or spray. You don't report whether yours has the original wooden floor gratings still in place. They can hide a small "lake" that sloshes around the boat, esp. when heeled.

Sometimes, the hull-deck joint is not sealed well any more and if you sail your boat vigorously, you can get water in that way. If your seats have cracks along their top edge, where they connect to the hull, water could get into them from there, on the inside.

There's also a chance that your hull has a crack that is well above the waterline. Your method wouldn't find a source of that unless you filled your boat to the level of the coamings with water, something that would most likely cause damage if you try this on land . . .

You don't write whether you keep your boat afloat or sail it dry. If kept on a mooring, another source of water may be rain water. If your seats have the original foam, that water may come out with a delay.

If after due consideration, you still expect water to come in through the hull, go push on the hull on the port side (also shift it on the trailer to be able to see everything). If the hull flexes, there may be a crack that "opens" when flexed. But you should be able to find that by inspection. If the hull is really soft, you may need to take the seat off with a Dremel or similar tool to strengthen the laminate from the inside and then glass it back in.

If you still have original foam, replace it. While you have it out, inspect the inside of the hull through the access port (e.g. by sticking in a camera on a stick and taking close-ups). Then fix the crack along the hull. Test sail the boat before filling with pool noodles and see whether water puddles on the inside.

Let is know whether any of these suggestions make sense and/or fill in some detail.
~ green ~ lake ~ ~
GreenLake
 
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Re: Finding a hull leak

Postby NHSteve » Wed Apr 10, 2019 7:46 am

Hi GreenLake

Thanks for all if the info!
My boat still has the foam so I guess my first action is to cut out an access hole and remove this foam, I have read another post regarding this issue and I think I can handle it.

My boat is docked on a lake and it seems to take on 20-30 gallons and then stop leaking.

I do still have the floor gratings and you are correct they do hide a small lake.

I like your suggestion that maybe I am looking at this backwards and the water I see coming out of the seat is actually water that came in from another source. I will have to investigate this theory more this weekend. I will tilt my trailer to direct more water to the stern and see if maybe the leak is from the stern area.

Anyway, thank a bunch for all of your suggestion.

Steve
NHSteve
 
Posts: 3
Joined: Tue Apr 09, 2019 5:09 pm

Re: Finding a hull leak

Postby GreenLake » Wed Apr 10, 2019 12:01 pm

If the hull fills to a set amount and then stops while moored on the water that implies that there's an actual leak such that water flows in until flotation chambers take over and then the water level equalizes.

It also implies that the leak is below the water line. For example, if the drain plug isn't tight in the transom. (I read, that some people take it out while the boat is moored, so it can't be swamped by rain).

CB gasket is also at or below the water line, so check for slow drips there. Actual hull punctures should be something you can see when the boat is on the trailer.
~ green ~ lake ~ ~
GreenLake
 
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Joined: Mon Jun 18, 2007 3:54 am

Re: Finding a hull leak

Postby NHSteve » Wed Apr 10, 2019 12:29 pm

Hi GreenLake
More good stuff!

I do not see a transom drain plug, would this have been a stock offering or is this something some people install for convenience?

What I do see is evidence of a patch near the transom on the floor, maybe a self bailing device was added and later removed? I have seen some weeping from here but at a much lower rate that the water weeping out from the port side seat.

I agree with all that you've said but I just can't figure out why when the boat had 2" of water above the open seat port why I did not see water weeping from the hull?

This weekend I will scam a way of putting a lot of water in that port side seat and try to find the hull leak.

Regarding the CB gasket, is it your opinion that I should see drips coming from that area if I fill the bout with 4" of water?
NHSteve
 
Posts: 3
Joined: Tue Apr 09, 2019 5:09 pm

Re: Finding a hull leak

Postby GreenLake » Wed Apr 10, 2019 2:28 pm

The way you see CB gasket drips is when the boat is in the water. I would NOT put 4" of water in my boat on the hard. That's so much weight that it can't be good.

One other thing you could do as you are planning on seat repairs anyway: after removing the foam, glass over any cracks between seat and hull.

If the cracks can be reached from your new access port, you could make that repair from the inside for slightly better optics (and to avoid having to paint the new patch).

Have you done fiberglass work before? Not really that hard a skill to pick up by doing.

Transom drain. My '63 has one and it looks original. Mine also has a floor drain (right behind the CB trunk). (That one I glassed over as it hadn't been used in years). Owners may have installed autobailers, but for those model years I think they did not come factory installed, at least by default - just judging by what I remember having read here.

If there's a patch in the hull and water seeping in that area, then that's where your issue is. The rate of seeping is not relevant: if you keep your boat on the water it will fill eventually even with a slow seep. That more water can come out of the cracked seat tanks is irrelevant if the source of that water is from inside the hull.

Check that repair near the transom to see if you can spot any cracks or defects around it. There really should be none.

Another alternative is that a crack is shaped so that it acts a bit as a valve, that is, closing against itself as you put a lot of water into the hull.
~ green ~ lake ~ ~
GreenLake
 
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