Need some advise on repairs...

[Scuba_Tacoma]

Hello,
I have access to a 1987 Grumman pontoon boat that stays in a wet slip on the intercoastal waterway. I recently took it out of the water to clean and drain the pontoons. The boat was sitting very low in the water and needed to be drained.

At some point either the original owner or factory put small holes in the bottom of the pontoons. These holes were plugged with a screw. As far as I know the pontoons have not been drained for at least 15 years. I removed the screws from the port side pontoon drained lots of water. Not sure exactly how much water but it drained for over an hour. My problem is that the screw on the port side pontoon will go in to a certain point then just spin. I am afraid this will not be a good enough seal. I do not think I should rere-tap the hole because a bigger screw would leave less threads to catch.. and a bigger hole. Any suggestions?
Thanks

 

[Grumman Historian]

Re: Need some advise on repairs...

Hi,

You didn't say whether the boat is draining or leaking from any other areas of the pontoons when out of the water and on it's trailer. If not, after it's completely drained, you might consider having the screw holes welded and the welds ground flush. First find the source of the water entry. If you have some leaks, they need to be dealt with.
You can also have a good welder install a hull drain plug at the aft end of each pontoon to avoid these type of future problems. They should be of aluminum since that is the hull material. Of course, these are only suggestions as you have requested, but I've done them in the past quite successfully on other aluminum boats.
You're welcome !