Tricks to Finding Leaks

[atengnr]

I ve got a water leak into the hull/floor space, but havent an idea where its coming from. Boat is 1968 safetmate, but water leak existed since new (family is original owner). After a boat ride, there will be about 20 ounces of water in subfloor. Leak is not from deck (water is there even if no one gets water into the boat). I recently painted hull - it showed no signs of a leak path. Could a leak around the bow eye allow water to get below the floor (it is located well above the floor level)??

Thanks.

 

[QC]

Re: Tricks to Finding Leaks

What material is this boat? Fiberglass? Aluminum? Wood?

 

[salty87]

Re: Tricks to Finding Leaks

anywhere there's a hole in the hull could leak...bow eye, bilge discharge, plug opening(s), rudder/shaft if you have those, outdrive if that's what you've got, exhaust, ... don't forget the rubrail too. water can get up under the rubrail when you're cruising and run down the inside of the full. check the underside to see that it's sealed to the hull all the way around. you can spray water from a hose to re-create cruising around, start with a dried bilge and see if it gets wet.

can you see into your bilge well? you might be able to see a trickle running down into the bilge. my exhaust is doing that (inboard). the trickle can be hard to spot but from the right line of sight it's obvious.

some peolpe have had luck finding leaks by filling the bilge with water (on the trailer in the driveway), see if it leaks on the outside anywhere. don't overfill and mess up your starter or electronics, though.

 

[CATransplant]

Re: Tricks to Finding Leaks

Where is the water pooling up? At the bilge? Somewhere else?

I'm not familiar with the boat, so is it an outboard or I/O?

If the water's in the bilge area, suspect the leak somewhere on the transom. Fasteners, a leak around the bilge plug, or anything else that penetrates the transom. Even the screws holding on a transom-mounted transducer for a fish locator can leak the amount you mention if they're not properly sealed.

If the water's elsewhere, then it's a matter of tracing down possible entry points.

 

[sdunt]

Re: Tricks to Finding Leaks

Paper towels are a great leak detector locator. once you isolate the general area of the leak, and the garden hose is the best idea IMHO. THen tape paper towel over the area of the leak and watch it the spot that gets wet 1st is the source.

Friend of mine showed me this when trying to find a very slow leak in engine oil pan. Cleaned area off, hung paper towel, waited 1 minute and bingo, found leak source..

 

[Scaaty]

Re: Tricks to Finding Leaks

I went nuts looking for the leak coming into the cabin on my 25 footer in the rain. Rubrail, lights, etc. EVERYWHERE!
Turns out when I taped over the rain drain holes in the windshield frame, it went away!

You can try filling the hull with water on the trailer, then look for a leak​

 

[atengnr]

Re: Tricks to Finding Leaks

What material is this boat? Fiberglass? Aluminum? Wood?

Boat is fiberglass, outboard. Very basic design, covered bow, splashwell in the back and thats about it. NO bilge open to the space between hull and floor (only access is via drain plug). I dont think the rubrail could do it because a leak there would cause water to leak into the boat (above deck) rather than below the deck.

Water is leaking into space between floor and hull. The only mounting screws on the transom (below water) have been sealed with polysulfide.

Could there be a crack in the hull that isnt visible by inspection?? On second thought, since a leak existed since boat was new 40 yrs ago, it would seem that an age-related crack isnt the cause??....

 

[QC]

Re: Tricks to Finding Leaks

My last question is does she leak sitting still? If no, then I like the rub rail splash test stuff. If it does leak while tied up then you need to look below the water line . . .

 

[atengnr]

Re: Tricks to Finding Leaks

My last question is does she leak sitting still? If no, then I like the rub rail splash test stuff. If it does leak while tied up then you need to look below the water line . . .

I dont know if it leaks sitting still, and I think ill check this 1st this season. I dont see how the rubrail could cause this?? HOw could water get between the floor and hull from there?? It looks like the hull meets the rubrail with the woven material and water could only leak straight through into the boat interior (above deck)...NOt arguing just trying to understand.

 

[studlymandingo]

Re: Tricks to Finding Leaks

What conditions are you boating in? Is it on a lake that is generally calm, or are you in some chop taking spray? My boat can sit in the water all day without a drop in the bilge; when I start cutting through some waves pushing spray to the sides, I get water in the bilge, sometimes a fair amount. I have a couple of good bilge pumps that push it out when I want it gone. I'm pretty sure it is coming in under the rubrail.

You stated the water is in the subfloor; is it making it into the bilge? The bilge isn't a big deal, but the subfloor is. Is there any rot or decay under the floor?​

 

[atengnr]

Re: Tricks to Finding Leaks

OK heres the story. NO real bilge area on this boat. One must pull a drain plug to get water out of the subfloor area. My Dad and I replaced the stringers and floor in 1997, and so Im not terribly concerned with rot there yet (all was replaced due to rot of course). This leak has existed since boat was new, according to my father, and I can vouch for about the last 20 yrs of it.

Being that this is a 15 ft boat, i use on small inlands lakes with relatively calm water (though I want to take out on Great Lakes this year). However, water leaks into the subfloor regardless. I have not yet launched the boat and let it sit in the water to see if it leaks this way. I really would like to get this problem fixed so that I dont have to worry about doing another floor/stringer job!!

The transom was another matter, but long story short, I am confident that this is not the source of the leak, and its now sealed up to save the wood

What I dont understand here is, how can water get in the subfloor from the rubrail area??? It doesnt seem possible with this boat. I think water would have to run through the fibers of the woven in order to make it to the subfloor.

 

[burroak]

Re: Tricks to Finding Leaks

I have nothing to add to finding the small leak. However; I did notice that you have a desire to take the 15' boat out on one of the Great Lakes. That boat is not safe on the Great Lakes. Even on what appears to be a calm day, straight line sheer winds come up and will capsize that little boat. I witnessed that very thing happening while on the Kenosha breakwater smelt fishing. Two died that night. Several boats capsized.

 

[atengnr]

Re: Tricks to Finding Leaks

I have nothing to add to finding the small leak. However; I did notice that you have a desire to take the 15' boat out on one of the Great Lakes. That boat is not safe on the Great Lakes. Even on what appears to be a calm day, straight line sheer winds come up and will capsize that little boat. I witnessed that very thing happening while on the Kenosha breakwater smelt fishing. Two died that night. Several boats capsized.

I appreciate the concern. Please let me know if Im way off here....I have used this boat many times on Lake Huron in years past, sticking < 1 mile from shore. I sort of stopped using it about 10 yrs ago there fearing that is just too much for a small aging boat out there. While the water is often too rough to exceed 15 mph comfortably, I have not felt that safety was an issue. If it got a bit too rough, I resorted to keeping the bow up and perpendicular to the waves (this seems to be a case where having a closed bow is helpful). Anyway what do i know?? Perhaps it was dumb luck that I wasnt sent swimming to shore.

 

[burroak]

Re: Tricks to Finding Leaks

I appreciate the concern. Please let me know if Im way off here....I have used this boat many times on Lake Huron in years past, sticking < 1 mile from shore. I sort of stopped using it about 10 yrs ago there fearing that is just too much for a small aging boat out there. While the water is often too rough to exceed 15 mph comfortably, I have not felt that safety was an issue. If it got a bit too rough, I resorted to keeping the bow up and perpendicular to the waves (this seems to be a case where having a closed bow is helpful). Anyway what do i know?? Perhaps it was dumb luck that I wasnt sent swimming to shore.

My experience has been on Lake Michigan (west) for 30 yrs. If you watch the weather, one can fish the near shore.

The particular incident that I cited blew up in just a matter of minutes. You know the local waters and have developed a comfort zone. I have used an open bow 18' Starcraft for all these years and have taken on my share of water. My preference is to quarter the waves; I don't knock out the bow canvas as often.

I do want to get to Lake Erie this year. Do you have any suggestions?

 

[QC]

Re: Tricks to Finding Leaks

It looks like the hull meets the rubrail with the woven material and water could only leak straight through into the boat interior (above deck)...NOt arguing just trying to understand.

Don't worry, we only nite around here once and a while

Most fiberglass hulls are two pieces, the "hull" and the "deck". Some boats the floor is molded into the deck without a separate floor, but they are still joined at the rubrail to hide the joint itself. Most boats I can imagine would leak to the bilge if the underside of the rubrail was not properly sealed to the hull. Just run your finger along the bottom of the rail and you should feel the sealant. Many boats, even new, have gaps there . . .

Edit: Just read your last post. We need a pic . . .

 

[atengnr]

Re: Tricks to Finding Leaks

No I dont have experience with Lake Erie.

 

[atengnr]

Boat Pics

Boat Pics

OK, the pics below show the boat, and I took a pic from the inside showing that the sides of the boat leading up to the rubrail are only a continuation of the hull woven material (floor doesnt connect there). Also the last picture shows the "bilge area" where the drain plugs are located to access the subfloor area.

Heres the link....

http://s147.photobucket.com/albums/r296/atengnr/?action=view&current=1177164638.pbw

 

[atengnr]

Re: Tricks to Finding Leaks

any more thoughts here??

 

[Plainsman]

Re: Tricks to Finding Leaks

How much water are you taking on? A cup full or gallons?
I was taking on a few gallons every trip. I went around the boat and resealed everything I could find with 3M 4200 and haven't had a problem since.

 

[atengnr]

Re: Tricks to Finding Leaks

How much water are you taking on? A cup full or gallons?
I was taking on a few gallons every trip. I went around the boat and resealed everything I could find with 3M 4200 and haven't had a problem since.

After a day on the lake, it will have up to 1 qt of water in the subfloor.