Need tips on how to find pesky hull leaks

[rangeryacht26]

Some background history...

My boat had been on the hard for about five years before I bought it. When I was checking out the boat, I noticed a musty smell and figured that it was leaking from the cabin top. There were stains around the chain plates and at various other places. There did not seem to be any soft spots on the deck, so I thought that all I would have to do is re-bed the deck hardware and steam clean the interior, and all would be good.

After I launched my boat, I found it has a leak that allowed about 2-3" of water to seep into the boat. I think the leak stops about at the water line, which would makes sense. I had the boat hauled out and low & behold, the water didn't come out. I did a inspection of the bottom while it was on the lift, and I could not see any cracks, blisters or any other defects. So I figured that the water had come in from the deck after a rain storm we had the previous night. I removed the water an dried the hull out, and the next day the water was back. The water did not seem to get any deeper so I did not worry about it, thought I would put it on my "fix it this winter list".

After I had it hauled out and checked for leaks, someone suggested that I "should have" filled the cabin full of water to see where the water was coming from, said something about "water pressure forcing it way back out". It seems to make some sense, but I can only fill the hull up to the top of the dagger board house (approximate 10-12"). I have removed all of the fabric and foam from inside of the boat and found a spot where there was a hard impact that cause the hull stiffener to crack in about four places . The impact area is at least 12" above the water line and you can barely see the cracks on the outside of the hull. I plan on fixing this before I paint the boat this spring.


This is where you guys come in...

I sail in fresh water and store the boat on the trailer, I would like to put on a hard slick bottom paint. We get very little growth if any on the bottoms around here. Since I have this leak problem would it do any good to use an epoxy coat or paint? Please send any ideas on how I can find the dreaded leak?

Thanks,
Kevin

[camaraderie]

Kev..an alternate way of finding leaks is by blowing AIR pressure into the boat with a big industrial type fan (sealing all around it) then using a soapy water mixture all over the boat and watching where the bubbles form. That's where your leaks will be.
I would not use any paint or epoxy until I found the leak.

[chucklesR]

Sprinkle chalk dust in the suspect areas, run a hose over it and wait. Wipe or vaccum the chalk dust when done (use colored chalk so you can see it better).

[sailingdog]

Don't assume it is the hull leaking. It very well could be a deck fitting or hatch. If you assume it is the hull leaking, you may end up chasing your tail.

Sprinkle the interior with powder, like talcum, and see if the leak shows up in the powder. It will leave trails through it... If the leak is in the hull, you'll see the powder get wet from the bottom up.

How good is your access to the interior of the hull. If it is coming through the bottom, it has to be a through-hull or other fitting like that.

[rangeryacht26]

Never in a million years would I have come up with the idea to use talcum powder to find the leak! I will give that a try, if that does not work I will try the air pressure/soapy water trick.

Again thanks for your input.

Kevin

[sailingdog]

Be aware that if the leak is in the cabin top, the water can often travel a long way before it shows up someplace you can see it... In many cases, it can travel along the overhead or sides of the boat for quite a distance before it gets where it is pouring down into the bilge.

On the cabin top, hatches, and through-deck fasteners are often the culprits.