Transom rebuild questions

[78 Thompson]

The total thickness of my transom was right around 1.950, it was 1 full layer all the way across of 23/32, then a 3' wide piece 23/32 and a 3/8"(about .344) piece nailed to that. Glass on transom is about .200, basically no glass over the wood.
So I was wondering if I should try to do something different, to eliminate the little 3/8 piece, maybe go with the one 23/32 and then 2- 1/2"(.468) pieces and a couple layers of 1708 I think that would be close at an estimate of 1.976, I could maybe eliminate 1 layer of 1708 if it starts looking to thick.
What do you guys think?

 

[Scott Danforth]

Transom specs are 2.0 to 2.25

 

[78 Thompson]

Transom specs are 2.0 to 2.25

Ok mine was probably about 2.0
My question is more of does it matter what size plywood I use to get there and do you guy’s think I should try to get away from using the flimsy 3/8 piece, like it was from new?

 

[Scott Danforth]

Two pieces of 3/4" laminated together.

 

[78 Thompson]

Can I get there, to 2” with only 2 pieces of 3/4?

 

[Chris51280]

yes. if you add the current thickness of the fiberglass and the added layers of 1708 you get there. each layer of 1708 should give you close to 1/8". depending on the filler on the fiberglass hull to the boards you need 2-4 layers of 1708 over the boards. and be within 1/16" flattness

 

[78 Thompson]

Another question I have is, my transom wood went all the way up to the seem where the top cap meets the hull, with no tabbing or anything on top of the wood. When I rebuild it should I stay 3"-4" lower and tab it in?

 

[Scott Danforth]

lower it about an inch max and tab it in

 

[78 Thompson]

Question on cutting steering cutouts. How are guys doing this, do I cut these out first, before cutting keyhole? Is there some specific angle or width it should be?

 

[todhunter]

I used an angle grinder with a sanding cylinder. The Mercruiser jig uses a hole saw. We will find out if my reliefs are big enough in a few weeks when I go to install the gimbal housing. If not...more grinding to make the reliefs big enough, then glass and gelcoat to seal it back up.

 

[78 Thompson]

I used an angle grinder with a sanding cylinder. The Mercruiser jig uses a hole saw. We will find out if my reliefs are big enough in a few weeks when I go to install the gimbal housing. If not...more grinding to make the reliefs big enough, then glass and gelcoat to seal it back up.

suppose its not worth buying the jig? How about drilling the holes for the gimbal housing, how do you get them square to the transom?

 

[78 Thompson]

I've noticed on a lot of transom rebuilds, guy's are cutting the bottom of the wood up above the drain plug, and filling it in with PB. Is this to keep the wood up away from the drain and possible water intrusion?

 

[todhunter]

suppose its not worth buying the jig? How about drilling the holes for the gimbal housing, how do you get them square to the transom?

If I recall the jig was north of $500. As much as I love tools, I don't think this "one and done" tool is worth it. Some folks use a tool they can mount to their portable drill that holds the drill square to the surface. Others have just drilled a hole in a block of wood on a drill press and used that as a guide. I plan on trying the latter. I'll start with a center punch, then drill a small pilot hole, then enlarge with the correct sized bit. I think you drill the holes slightly oversize for the bolts so you have a little bit of wiggle room.

I've noticed on a lot of transom rebuilds, guy's are cutting the bottom of the wood up above the drain plug, and filling it in with PB. Is this to keep the wood up away from the drain and possible water intrusion?

I noticed the same and just copied them. Yes, I think the idea is to keep the bottom of the transom wood as far away from water as possible.

 

[JASinIL2006]

I used a several pieces of plywood glued together, about 2.5" thick. It worked well, but I did need to pick up a drill bit that was slightly longer than the normal. I figure I still saved about $480 over the jig...