Leaky aluminum boat

I have a 14' 1960's era aluminum boat. However, it has a slow leak so it cannot be left unattended in the water. Twice I have tried to fix it by applying Gluvit and Coat-It epoxy sealer to all seams, rivets, and other places of possible leaking. (I did this work on the outside of the boat, since the seats & hardware would interfere with working on the inside.) I have replaced the drain plug. However, the problem continues. Any ideas?

 

Luckily my hobby was building airplanes so I have a pneumatic rivet gun. I had a leaky aluminum boat. I pulled it out of the water so it could thoroughly dry. Then I put it back in the water and I watched to find the source of the leak. Then with the rivet gun and bucking bar I re-set the rivets in the leaking area. This is the same method used to originally construct the boat. It took care of the problem and it was still leak free when I sold the boat years later.

 

That sounds like it worked out well.

Regarding the watching to find the source of the leak, I can't do that because this boat has ribs & supports that obscure the view, as well as a wooden floor and seats, etc.. So I'm just trying to attack all possible sources from the outside. But for some reason I am missing something, or the epoxy paint was not adequate, or...

 

I assume you did Gluvit on the outside of the hull. I bet if you look you'll find some pinholes or open cracks along a seam or at rivets. If you beach the boat it's really hard for something painted on the bottom to last very long.

 

Years ago I borrowed a canoe to do the 117 mile river paddle 'Schuylkill Sojourn'.
The old canoe developed a pinhole leak that I couldn't find.
One of the old-time paddlers showed me a trick

- turn it upside down and smear a really thin coat of fine mud on the bottom
-let it dry in the sun.
-flip it, prop it up on a couple of river rocks
-pour a couple buckets of water into it and wait a couple minutes.
=The dried mud makes any small drop of water seeping through a pinhole / seam really easy to see.

 

So Pilot Dane, do you think this is kind of a lost cause (keeping & using an old leaky aluminum boat), and I start thinking about replacing it? I thought it would be fun to have a kind of vintage boat--but not if it is going to continually have leaks.

 

If you've ever owned a boat long enough you know you've got to sometimes take things apart. You probably have to remove the interior to spot the leak and for the fix.

 

Flex seal will patch a screen door in a boat (so says the commercial) I would try some of that.

 

most all aluminum boats with rivets leak in my experience, the manufacturers eventually went to all welded or at least no rivets below the water line so if you want to keep the boat in the water full time I think you may want to just upgrade to a newer boat, other sources of leaks besides the hull would be LiveWell if you have one or other accessory like fish finder transducer screwed to the hull, if you want to try to fix this one but may be temporary might try a couple coats of aluminum boat paint on the exterior hull. install an auto bildge pump may work till the battery is run down for a slow leak a battery could last months, but probably better off selling it to someone that will not keep it in the water full time and they can switch on a bildge pump when on the water if they need to.

 

Gluvit is very similar to Flex Seal. It can be waterproof but being just a painted on layer on the surface it's easily damaged. If the boat is left in the water osmotic pressure tends to create blisters underneath so it's not what I'd call a permenant solution.

One way to definetely seal the rivets and joints is to use a product called "Proseal". There are several products by the same name but you want the aviation one used to seal aircraft wet wing fuel tanks. It comes in two parts like an epoxy and is a pretty good adhesive in addition to being a great sealant. It is best if you drill out the leaking rivets. Then apply Proseal, stick in the new rivet and squeeze or hammer the rivet in place. I've used the version from Thiokol but 3M and others also make it.

 

Or, find a local shop that does MIG welding...

2023 Welding Cost: How Much Are Welding Shop Rates? (homeadvisor.com)
https://www.homeadvisor.com/cost/wal...gs/weld-metal/

Machine Shop Rule #1 "It can't stay seized if it is molten..."
Inverse Machine Shop Rule #-1 "It can't leak if it is TIG welded solid..."