riveted aluminum boat leaks

[beckoning]

I'm hoping to get good advice.

For 10 years, I’ve had a 19', 1989 SeaNymph Great Lakes Special, riveted heavy gauge aluminum hull, and plywood floors I replaced in 2015. The boat is an extremely durable, and excellent for big lake fishing: high gunwales, very deep V, heavy gauge aluminum. This season, it developed a leak so upon 3 hours of trolling, the bilge pump will pump out about 3 gallons of water. The boat has a live well below deck, in front of the helm. The live well is dry, and is never used. I think the live well draws from below the water line in the stern and exits (via a pump) starboard amidship.

There is a leak somewhere. The hull is completely out of the water on hoist when not fishing. My first task is to assure the live well inlet is sealed to see if that stops the leak. If not, once I pull the boat for the winter, how can I find the leak? I’ve thought of putting it on the trailer, making sure it is level fore-aft, port-starboard, then filling it with water dyed with black or blue dye up to the bottom of the floorboards. Then with a flashlight look for the leak. Could also do it with un-dyed water, but it would be harder to find the leak. Anyone out there with another good way to find a leak in a riveted aluminum boat?

Then, once I find the leak, is there a good sealant anyone can recommend? I read high praises about Alcoa gutter sealant. I don’t want to coat the bottom with epoxy as that will add a lot of weight to the boat. I had a row boat once that was epoxied, and it weighed a ton.

Need to find the leak, then seal it. Removing the carpeted plywood floor is not an option, so replacing rivets is not an option.

Ideas? Thoughts? Thanks in advance.

 

[GA_Boater]

First - Don't fill the boat with water up to the deck. If you have wet foam, you will make more wet foam. Also, water weighs about 9 pounds per gallon. If it takes 100 gallons to reach the bottom if the deck, you may find more than a leak. Like damage the trailer or the boat from the weight.

Second - While it's on the lift, examine the hull for missing rivets or rivet heats. The heads can be torn off by beaching or hitting something the water. Closed end rivets can be used to replace sheared headed or missing rivets from outside.

Third - Before putting the boat on the lift, remove the fuse for the bilge pump. After the the boat is in the air, look for drips. Put the fuse back in before using the boat again.

Fourth - If your boat was a gutter, gutter seal might work. But it's a boat that moves through water at much higher speeds than a gutter on your eaves.

Fifth - There are no short cuts.

 

[ahicks]

Maybe plug the inlet and outlet for the live well, then fill that to see if any of that is leaking.

 

[TyeeMan]

Get the boat on the on the trailer and as was said previously, look for any damaged rivets. Touch and feel any suspect rivets, see if they are loose in the hole.
Previously I have put water in aluminum boats while on the trailer. Just a few inches was all it took and I could see the leaking rivet. In the past I've drilled out the rivet and replaced with a pop rivet and silicone, that lasted for years. I've also used JB weld which also lasted years. Otherwise there is a 3M sealant for marine use, , 5300 I think it is? Somebody please correct me if I'm wrong on the 3M sealant.

 

[Bob_VT]

I do not recommend water into the boat - not healthy for the flotation which my not ever dry out!. Most aluminum boat leaks can be visually spotted due to a popped or loose rivet

3M5200 is the marine sealant and will hold up under speed of a hull.

I have also applied gluvit to seal leaks. It will flow around rivets

Then again you might have a plumbing isssue with the drain/fill lines for the livewell

You are going to have to hunt for the leak and I would strongly suggest visually

 

[roscoe]

Have sealed, replaced, and even redneck fixed rivets on several boats.

Best/easiest for your situation, is to replace the bad one, using a Closed End pop rivet, coated with 3M 5200. Then apply a drop of 5200 over the outside of the rivet.

If its just a seepage leak, it will be hard to locate.

Hopefully it is livewell related.
The old plastic pipes used years ago tend to get brittle and crack over the years.
But its easy enough to seal up the inlet, and won't be an issue since you don't use the livewell.

You could try putting some water into the inlet with a garden hose, and seeing it it ends up in the bilge.