transom advice

[islander2617]

were to start...well started out to replace the floor and like opening the walls on an old house I am looking at replacing the Transom in my 26ft Starcraft Islander which has a 305 inboard. Never done this type of job so looking for some advice. What is going to be the best adhesive for attaching the plywood to the aluminum does anyone have a brand name they prefer. For the plywood would it be better to use 3 sheets of 1/2 or 2 sheets of 3/4 and would you glue or epoxy the sheets together.

 

[ondarvr]

The number of sheets of ply doesn't make a difference, just get to the thickness required.

​Epoxy or a waterproof glue is fine. There are many bolts going through the sheets of ply and the transom, it's not going anywhere.

Is the current ply glued to the transom, or just sealed?

 

[islander2617]

it looks to be glued to the aluminum

 

[jbcurt00]

it looks to be glued to the aluminum

Thats not factory....

SC didnt glue the ply to the aluminum transom skin, no need for that. It'll make it challenging to pull the old and prep for the new.

Well sealed exterior grade (NOT pressure treated) or marine plywood will be sufficient.

Make sure to seal the keyhole cutout very very well.

Welcome to iboats and to the Tin-sanity...... Take a look thru the tin boat rehabs posted here:
http://forums.iboats.com/forum/owners-groups-by-manufacturer/s/starcraft-boats

Good luck w your project
@Watermann
jasoutside

 

[islander2617]

Thanks for the advice so what would use to seal the ply and just bolt the ply to the aluminum don't glue or silicone.

 

[Tnstratofam]

You can use epoxy, urethane spar varnish, or woodonglass's Old Timers Forrmula to seal the wood. The transom wood will be held in place fine by the transom screws and gimbal housing so no glueing to the alluminium skin is needed.

No silicone on the boat anywhere. If you need a sealant for rivets or any through hull fittings you should use either 3m 4200 ( It's removable ), or 3m 5200 ( It's not easy to remove ) The 4200 is good for bolts or fittings that you may need to remove for service or maintennce where the 5200 is good for rivets or fittings not meant to be removed later.

Oh and welcome to the Starmada! Pics when you get a chance please. We all love pics.

 

[jbcurt00]

I'd recommend epoxy to seal the plywood after its glued together, BUT it is a slower process to cure between coats (you 'need' 3 coats on each side and do the edges w every coat, so they get 6), its more expensive then the others TN mentioned, AND most importantly, it MUST be painted after sealing. Wpoxy isnt UV stable so it must be covered.

Make sure you plan for the thru the keyhole dimension, a Mercruiser outdrive requires a 2-2.25in finished thickness from exterior of the transom skin to the inside face of the 'horse collar' added plywood to reach final thickness. Guessing w a GM 305, its a Mercruiser setup, not Ford or OMC (Right?)

Jas's rebuild of his Islander features swapping an OMC setup for a Mercruiser. Well worth the effort, but is not an extremely easy process.

 

[islander2617]

That's great thanks again........here are a few pics

 

[jbcurt00]

Yep, should need 2-2.25in thru the keyhole..

Means about a 3/8in plywood horse collar around the keyhole. W sealing, the aluminum transom skin and 2layers of slightly less then 3/4in ply, you should be at 2.25 after adding the 3/8s

 

[islander2617]

for sealing around the horse collar would you suggest the 3m 4200