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Fibreglassing the transom

PostPosted: Mon Sep 07, 2020 2:07 am
by John.hawkswell
Hi all

Im reading the manual at present. Have not got the plans/kit yet.

I cant see anywhere about glassing the inside of the transom.

Is the inside of transom just epoxied?

If glassed at what stage is it done?

Is the inside best glassed before fitting it to the boat same as sides and topsides?

John

Re: Fibreglassing the transom

PostPosted: Mon Sep 07, 2020 4:17 am
by TassiePete
Hi John,

I did not glass the transom on the inside. However, I used some 4" glass tape on the inside joints to the hull panels and I left a few ss screws in there. It is certainly easier to glass/epoxy all the panels and bulkheads before fitting, except the fwd third of the lower hull panels. They are a beast to pull together at the bow as it is, and with glass it will be even worse. If you like some more reading, you can download the 'Kermadec' picture book from my web-site (about-me page). It might give you some more useful info.

Cheers,

Peter

Re: Fibreglassing the transom

PostPosted: Mon Sep 07, 2020 4:21 am
by John.hawkswell
Thanks
Ill have a look

Re: Fibreglassing the transom

PostPosted: Mon Sep 07, 2020 1:48 pm
by SMHolmans
I intend to 'glass the inside face of my transom when I do the same to the cockpit. In fact, I intend to 'glass the entire exterior of the boat -
I can't see why not to do so.

Like Pete says, be sure to glue and screw the transom in place, to the hull bottom and side panels - don't rely on fillets to hold it together. I glued and fastened my transom with lots of epoxy and bronze screws. You really don't want to worry about losing your transom if you get into difficulties. Dry joints are bad practice and unsafe!

Re: Fibreglassing the transom

PostPosted: Tue Sep 08, 2020 6:38 am
by riverron
Hello John,
I glassed the entire transom for the most part. Not with one big sheet, but as the different parts came together like the bottom, sides and seat decks. Mainly where I overlapped as pieces were added. There may be a small section under the seats that didn’t get glassed, but it received many coats of epoxy. Anything showing definitely was glassed with at least 3 coats of epoxy.

Thanks
Ron

Re: Fibreglassing the transom

PostPosted: Tue Sep 08, 2020 12:32 pm
by buckeye
Regarding screws in the transom.

Do you really think adding screws through 1/4" ply is that important with a large 1" fillet and interior and exterior sheathing?
I still have time to add them but don't have any in right now.

Re: Fibreglassing the transom

PostPosted: Tue Sep 08, 2020 3:40 pm
by SMHolmans
If you decide to glue the inside of the joint between the hull bottoms/sides and the transom, you will need screws to pull it up tight. The screws cease to have any purpose once the joint is cured - I only used bronze screws so I didn't have to pull them once the transom was installed.

Re: Fibreglassing the transom

PostPosted: Tue Sep 08, 2020 4:05 pm
by TassiePete
The thing about glass is that it only works in tension. The glass on the transom overlapping onto the panels on the outside will help to keep the transom from being ripped out of the boat ( although I am not sure what might ever cause such a thing ). The glass tape on the inside of the joint doesn't do much.
On the thin panels, the glass gives the structure its strength ( in some sense, the plywood is only there to keep the glass in place ). The transom is a thick chunk of plywood supported by cleats, seat-backs, etc. and has plenty of strength in itself.
When fitting the transom, some screws will be necessary to keep things in place while applying the epoxy glue. I have decided to leave a few stainless steel screws in there. They are completely embedded and they will outlast most of the other bits on the boats (and myself). The screws certainly don't do any harm and I am sure the boat won't fall apart without them ...

Re: Fibreglassing the transom

PostPosted: Wed Sep 09, 2020 11:33 am
by slick95
Regarding stainless fasteners in wooden boat construction this might be important to consider:

https://boatbuilders.glen-l.com/59404/b ... ing-boats/

Bronze hardware can remain in the boat forever.

Jeff

Re: Fibreglassing the transom

PostPosted: Wed Sep 09, 2020 3:45 pm
by TassiePete
Ah, the old stainless steel without oxygen problem. Stainless steel (particularly 304) can/will corrode if deprived of oxygen in a wet environment. Exposed stainless steel under water (especially salt water) can suffer, no argument (then again, what about rudder fittings ? They often made from 316).
Stainless steel embedded in epoxy (hence dry) will be fine. If any screws in these conditions are corroding, then the plywood around around them (that is what let the water in) has a much bigger problem. The plywood will be swelling and rotting before the screws are in danger.