Finding a leak???

[iggyw1]

Quick question guys. I have a 1991 Lowe riveted aluminum boat. It is new to me. Took it out and it has a small leak somewhere. It has a floor in the boat. I installed two round inspection plates in the floor so I could try top see where the leak is. The boat is dry in between the front and middle seats, and seems to be dry between the middle and rear seat. This leaves only under the rear seat and behind the rear seat (between the rear seat & transom) where the leak is.

Here is my question. Is there any truth to filling the boat with water, put the drain plug in, and the water will come out of the hull at the bottom where the leak is? If so, and if it is along the transom where it meets the floor, can I put some sealant over this area inside or outside of the boat? Thanks.

 

[airshot]

Filling the boat can work but has it's dangers...to much weight can damage hull or trailer. If you choose to use that method, use a smaller amount and move the boat by tilting the trailer to find the leak. Chances are it is a rivet and they can be tightened if you can find it. If the bottom if the hull is foam filled you may end up soaking ( waterlogging) that foam. If you can't find the leak, there is a product called gluvit that most folks use. After cleaning inside the hull, it is painted on around rivets and seams and works well.
The bad part is, the floor should be removed to do it properly. How bad is the leak ?

 

[iggyw1]

Filling the boat can work but has it's dangers...to much weight can damage hull or trailer. If you choose to use that method, use a smaller amount and move the boat by tilting the trailer to find the leak. Chances are it is a rivet and they can be tightened if you can find it. If the bottom if the hull is foam filled you may end up soaking ( waterlogging) that foam. If you can't find the leak, there is a product called gluvit that most folks use. After cleaning inside the hull, it is painted on around rivets and seams and works well.
The bad part is, the floor should be removed to do it properly. How bad is the leak ?

The leak is pretty bad when I am underway with the boat, but sitting still, there is hardly any water. I am trying to figure out why I am getting a lot of water when the boat is underway. The faster I go, the deeper the water gets behind the rear bench set. i have a 14 ft. Aluminum Lowe deep 'V' boat. I opened the inspection plates today while I was out there and things look dry other than behind (and possibly under) the rear bench seat. Cannot see anything coming in and running down the stern. I will look into that "glove it" if I can find the leak. Thanks.
EDIT: I know when I am going full speed, the bow is up high than when I am sitting flat, and the stern is down more. That's when a lot of water comes in somewhere. I have a new bilge pump & she is pumping a lot of water at fll speed especially.

 

[airshot]

Crawl under and look for missing or really loose rivets. Sometimes a rivet or two can pop out. When underway all the water runs aft so it may appear to leak more ( just a guess here). Unfortunately the best way to find and fix is to remove the floor, unless you find some missing rivets or hull damage causing the leak.. Wish I could be more help..

 

[Chris1956]

Boats flex when under power. That flex could open your seam more. Can you have someone drive the boat, while you look for the leak?

You might try to mark it with a crayon or something that will write underwater.

 

[iggyw1]

Thanks for all of the input. I may end up taking the floor up, but first, I will try to find the leak by #1- Fill the boat with water then raise and lower the front end to see if I can locate it this way. #2- Try to let my grandson drive the boat in a calm bay and I can look under the floor after removing the covers on the inspection plates that I added for the purpose of checking things out under the floor. #3- Removed the floor in the boat (which I will definitely save for last). Also, I installed some bolts thru the stern to add a motor mount when I bought the bolt last fall. I used a good sealer, but it may be a bolt leaking thru. I do not think so, but you never know. Thanks again guys!