Aluminum Patch Advise

[EMO870]

Hey all. Great forum here. I have a 16' smokercraft sportsman sled that the previous owner drilled a hole for a through mount washdown pump. The pump he had was from harbor freight instead of a marine washdown. I've tried to mount a marine washdown pump but honestly just don't like the plastic components so I took it back. It isn't a huge priority for this boat so I want to plug the drilled hole in the hull/transom. Wondering if this is what you would do. I was going to buy a small piece of aluminum sheet metal, cut a square that is larger than the hole, spread two or three circles of DAP Marine Silicone, and use 4 screws on the corners with addition silicone in the screw holes. This patch would be on the outside of the transom. How does that sound?

I have heard you can just use teflon tape and a plug but I've read some horror stories of these plastic through hull fittings cracking and boats having leaking issues. I duck hunt the lower Columbia so I want to do this right. Seems like a small weld job but if you think this would be a better idea, a few contacts in the Milwaukie area would be appreciated, however, I think the patch idea is sufficient. It is behind the jet pump so function over looks is fine. Thanks all.

EMO870

[KD Fisherman]

I would either use the piece of aluminum sheet metal with 3M 5200 (available at Home Depot) and stainless screws or blind stainless rivits or install a brass or stainless garboard drain in the hole with 5200 and stainless screws. Where is the hole on the transom located? How big is the hole?

Cheers,
Kyle

[EMO870]

Hole is approximately 1" about the size of the drain plug below the waterline (at the lowest point). What is a garboard? I'll find the 3M 5200. Anyone else have opinions? Thanks for the support Kyle. Much appreciated. I think this is what I'll do after visiting the Depot.

Originally Posted by KD Fisherman

I would either use the piece of aluminum sheet metal with 3M 5200 (available at Home Depot) and stainless screws or blind stainless rivits or install a brass or stainless garboard drain in the hole with 5200 and stainless screws. Where is the hole on the transom located? How big is the hole?

Cheers,
Kyle

[KD Fisherman]

I have a picture of the garboard drain in my gallery (don't know how to post pics in a reply) but basically similar to the transom drain plug. It would fill the 1" hole and may not look out of place since it is designed for through hull penetrations.

Cheers,
Kyle

[Gundog]

I take it the hole is below water line. I would not mix SS and aluminum below the water line because of galvanic corrosion and sinking. Aluminum sheet metal patch held on with some JB weld and aluminum rivets.

Mike

[Ziess]

Depending on your ability you could easily use just the sheet metal and 5200 and not have to put anymore holes or screws in the hull. Just keep in mind that 5200 is permanent and cannot easily be removed.

[Willie Ketchum]

I had to do that once, here's what I did:

I used a hole saw to cut a piece of aluminum same thickness as the hull to just fit inside the hole. Then cut two more discs with a bigger hole saw to overlap the repair by 3/8 or 1/2 inch. Use one 1/4" s.s. bolt and nylock nut thru all 3 pieces to clamp and use epoxy or 3M sealant to glue the whole deal in. No additional holes in the hull, and a strong reliable patch.

[EMO870]

I was wondering about the SS screws and aluminum patch. I've never used JB Weld. My boat is painted (or powder coated whatever they do at the smokercraft factory. Do I need to take it down to bare aluminum or will the JB Weld work over the existing painted surface? Of course either way I will clean it with a degreaser. Thanks a ton everyone.

EMO870

Originally Posted by Gundog

I take it the hole is below water line. I would not mix SS and aluminum below the water line because of galvanic corrosion and sinking. Aluminum sheet metal patch held on with some JB weld and aluminum rivets.

Mike