Transom core materials

[cSickNick]

Question;

Has anyone replaced a transom with any materials besides plywood? For example, has anyone used Seacast as the replacement transom core material?

I realize wood is good, but are Seacast type of materials better?

Your thoughts. Thanks in advance

- Nick

[Briguy]

I was just at a yard last night and saw a transom done with seacast. The guy had an old 22-2 aquasport. He cut out about the top 6 inches of the transom and raised it another 5" for a 25" motor. He made a plywood mould and poured seacast in. When dried, he removed the wood. To his surprise, the seacast shrunk and cracked in the corners. OUCH! That is not where you want a crack. Anyhow he was going to fill in the corners and then glass over it. I am not impressed with seacast. I redid my transom on my 23' and filled it in like an inboard with a cap. I used 2 3/4 inch marine ply boards with glass in the middle and then 2 layers on the outside and inside up to the rubrail. For the cap, I used 5/8 inch corecell. With only one coat of light glass and resin on each side, I can jump on it. Corecell is strong.(it looks smooth on the outside and like a honeycomp on the inside) As for a transom, I think what my fiberglass guy uses now is a very high density foam that is light, easily sandable and will never rot or let water seep.

[FELLOW-SHIP]

HA NICK
I LOOKED INTO THE SEACAST STUFF BEFORE I DID MINE WITH PLYWOOD. I DIDN’T KNOW IF IT WOULD REALLY WORK AS GOOD AS THE ADVERTISING SAYS AND I KNOW PLYWOOD DONE CORRECTLY WOULD LAST A VERY LONG TIME. ON THE NEW COMPOSITE MATERIAL TRANSOMS THAT ARE NOW BEING DONE I HAVE NOTICED THAT THEY WILL USUALLY USE A THICKER WALL OF FIBERGLASS ON BOTH SIDES OF THE COMPOSITE MATERIAL THEN WHAT YOU HAVE ON OLDER BOATS. IF I HAD TO DO IT ALL OVER AGAIN I STILL WOULD USE WOOD.
FELLOW-SHIP [img]images/icons/cool.gif[/img]

[TUGBOAT]

I just redid My transom with "Poly Mac" 24# Density foam.It took a lot of research ? If You were to get hit in the Head with a piece of this(2x4) size You would fall before it would Break!
Heavy,Hard & closed cell.Works really easy.I was worried about compression @ motor mount.Thickened the fiber a lil'.Water cannot creep.I hope I made the right decision,I'll let Ya know in 20 yrs Ha Ha.Maybe the diff. in weight will give Me another 10 KNOTS !!!!!!!'83 MA
Scream'n Reels

[cSickNick]

Thanks again for the feedback on this.

While pondering what to do with my failing transom (last summer), I ran into a "old timer" fiberglass man. He would not listen to anything but replacing the transom back with marine ply. He said " How old is your boat?" I said "25 years old". He said "I will guarantee the new plywood transom for 25 years". I said " Great, when will it be done?" He laughed " One week after you remove the old one!". I said (of course, he did not hear) "Smart Ass!".

Here is what "I" did;

- Removed engine, hardware, etc off the transom
- Cut the (already) cracked transom cap off (i used a dremel ceramic bit)
- Cut(dremel) the inside fiberglass transom liner ~ 2 " from the sides and bottom. (Note: I had the access through original outside vents, rear seats and a newly planned Bomar hatch cutout in the motor splashwell/bildge.)
- Remove the rotten transom core through the top and/or the inside. ( I used the old New England chain saw for most of it! Careful!!)

With the old transom core and inside fiberglass liner removed,

Here is what "he" did;

- Make a template (cardboard) of the transom
- Using the transom template, mark and cut out two pieces on 3/4" marine ply

Now he needed to make the 2 transom pieces into 4 pieces in order to slide down and around the top deck rear corners of the transom cap. He just cut vertically ~8" off each piece on opposite sides to staggered the seams.

- Wet pieces and inside transom with resin, slide new transom pieces into place through the top
- From the inside tape and resin all seems
- Re-drilled holes for motor, hardware, splashwell and bilge drains
- Had a SS transom cap/plate made
- Re-mounted engine

Then "I" went back to fishing!

- Nick