Tsunami transom replacement

[bigeasy1]

I've finished removing all the rotted wood from my 74 Tsunamis transom,and will shortly be installing new marine plyood.
I felt that the glass skin was very thin,so we laid up a layer of mat,and a layer of 1708 to build it up,and make it a bit stronger.

I've made my pattern,and plan on using two sheets of 3/4" marine fir plywood for the core.I have a few questions for those who have done Tsunami/Scepter transoms like this.

#1--Did you glue both sheets together,and install as one single piece, or did you place one sheet in and then glue the other to it.

#2 The original transom drain hole was offset to the port side a bit,because of the keel stringer.This would prevent getting all the water out when the boats on the trailer.

I was thinking of drilling a new drain hole in the center at the lowest point,and leaving the keel stringer stop just short of the transom.In this way i don't have to worry about a limber hole clogging up.Do you think the stringer has to be tied in?
Any input would be appreciated.Here's a few pictures. Thanks all.



Applying the cloth




applying more cloth



finished wetting out




tabbed in

[WillyC]

I would think that tieing in the center stringer to the transom would be important. I'm not sure what power plant you are planning on going with but if it is outboard then I would add a knee to the center stringer. If you go back with inboard/outboard then you may not have the room. Here's a couple of pictures of what I did. I have a 20' sf and will be hanging an outboard on the transom notch. I used coosa for the transom and the knee. I put a small limber hole in the base of the knee. If you went this route you could easily make the hole larger to accomodate the transom drain. Hope this helps.

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[strick]

Ditto what will said. You can make a 4"-5" half moon cut out and still be able to put in your drain however the out drive may get in the way.... not sure how much room you have. If you don't have enough room for that then simply put a big limber hole in the center keel near the transom and place your drain plug off center a bit. I think the keel should tie into the transom. On the core, I've always made up the entire core first by laminating the 2 pieces of 3/4" ply with 1708 between the two. then glassed the core to the transom. Keep the pice coming Capt mac.

strick

[warthog5]

then simply put a big limber hole in the center keel near the transom and place your drain plug off center a bit. I think the keel should tie into the transom. On the core, I've always made up the entire core first

It will be easier to do and get a good bond with the 2 sheet's of plywood laying flat.

If your putting a transom cap on the boat and I assume you are. It will be much easier if the transom core is cut down at the top, below the outside skin the thickness of the top cap core with the proper camber cut in it.
The creates a shelf for the core to sit on and have a even bend to it. It also helps so that the cap matchs the washboards.

[Capt Chuck]

I was thinking of drilling a new drain hole in the center at the lowest point,and leaving the keel stringer stop just short of the transom.In this way i don't have to worry about a limber hole clogging up.Do you think the stringer has to be tied in?

I might catch hell from you glassmasters but I had a discussion with Mr Potter on this a few years ago. Don't worry too much about that center stringer. Your masive box stingers/grid system give you all the hull support you need. That keel piece running a few feet up was put there in the early 70's to beef up the keel for the roller type trailers that were being used back then. Your not providing much hull support with that thing in place.
My '78 didn't even have one, just a half of PVC pipe glassed in to defect and channel bilge water aft

In this shot looking aft from the back of the fuel tank, you can see the PVC Pipe I cut away to install my thru hull transducer.



In this shot Mike @ Wildfire cut it completely out during the transom rebuild.