Replacing the transom on an Aluminum boat

[yam350yfm]

I just bought a mid-1980's 17' aluminum boat that has a 70HP outboard and the transom needs to be replaced. The wood transom is sandwiched between aluminum skins on the inside and outside of the transom. The center of the transom is pulling away from the splash well. I assume that was caused by water intrusion where the holes for the outboard are. It appears that there is an aluminum cap that is held in place with some small nail type fasteners that probably went into the wood. The outer aluminum skin has 20 or so fastener's of some type, some are screws, some are through bolts, and then there are some rivets. I have replaced transoms on fiberglass boats so I know how to form and epoxy the transom, I am just not sure how to remove the old transom on an aluminum boat. Here is what I think needs to be done:
1. Remove the outboard
2. Remove the outer transom board spacer that was added over the aluminum (oddly enough this is not rotted)
3. Remove the aluminum top cap (not quite sure how)
4. Remove all screws and bolts from the transom
5. See if the existing transom will pull out at this point

I am not sure how easy it would be to access this from the inside as there is an area that has the battery, oil tank, fuel tank, etc that would be in the way for access to the inner aluminum transom panel.

The transoms I replaced in the past were done with 3/4" marine plywood epoxied to seal them, including the holes. I planned to do the same with this one. I did price out Starboard composite but that was very costly. I guess another option would be to pour a transom with Seacast, just not sure how that works out on an aluminum boat.

Any tips or links to photos on how to disassemble, or pointers from those who have done it would be appreciated.

 

[Tacklewasher]

Re: Replacing the transom on an Aluminum boat

Loads of tips in the restoration forum as lots of guys have done this and documented it.

But your steps look fine. I plan to do mine soon and will just be using plywood, sealed as you described. I can't see going to the cost of Seacast for my boat. The plywood has held up for a long time and was not even sealed.

 

[yam350yfm]

Re: Replacing the transom on an Aluminum boat

What the problem with the current one is that it has pulled away in the center where the motor mounts about 1 inch from the slash well. I assume this means the plywood is shot. It would make sense that the water was getting to the wood via the mounting holes for the motor. I plan to take pictures and document the process for posting that others can refer to.

 

[ezmobee]

Re: Replacing the transom on an Aluminum boat

Did mine last year in a similar fashion as you described and it wasn't a huge deal. Good luck with your project. Post over in the restoration forum with any specific questions you might have.

 

[yam350yfm]

Re: Replacing the transom on an Aluminum boat

Tacklewasher, thanks I have posted on the restoration forum.

Ezmobee, thanks, I checked out the photos of your boat and it is very nice, something anybody would be proud to own. I plan to document the work on my boat along with some pictures of it out on various Wisconsin lakes. I plan to bring the boat out of storage in a couple of weeks and I figure the work will take about 3 weekends. Just need to get some other work around the house done too so I am shooting to be in the water by Memorial Weekend!

 

[ezmobee]

Re: Replacing the transom on an Aluminum boat

Thanks! I did the majority of the "awakening" and restoration 4 years ago. Painted it and replaced the windshield a year later, and did the transom last year. This will be it's 5th season of use and we've had a lot of fun with it. Right now I'm rehabbing a different trailer that I got really cheap from Craigslist. When I'm finished I'll switch it over and sell my old trailer.