Bulkhead Blues

[Stephan]

Gentlemen-
My bulkhead aft of the engines is delaminating. The picture below was taken looking forward from above where the strut pad is located on the Port side. This is the aft side of the bulkhead exposed to under the deck and under the cockpit side storage.



Part 1 is the bulkhead from under the side deck to deck level. It is thin (3/8ths?) plywood and well tabbed to the hull. It is in fairly solid condition - better than it looks in the picture- with some end-grain rot at the bottom.
Part 2 is a mahogany beam running the width of the boat. It has end-grain rot but is also more solid than the picture presents. It is screwed to #3 and is where the forward end of the cockpit lands as well as where the engine box hinges are fastened.
Part 3 is plywood (1/2"?) tabbed to the hull on both sides. There ain't much to it with the transmission coupling, exhaust, limber hole, etc. all taking up space. A larger view of the bulkhead behind the Starboard engine is below.



I am inclined to repair the lower portion of #1 by replacing the bottom few inches with new like plywood
Install a new #2 (insert crap joke here...) made of oak or mahogany treated with thinned epoxy.
Grind the aft tabbing away from #3 and remove it. Epoxy a new #3 of 1/2" plywood treated with thinned epoxy to the existing forward tabbing and tab it in on the aft side.

This sounds like a slap-dab job to me too but I don't understand what I'm compromising with this approach.
Thanks in advance for your advice.
Stephan

[CaptPatrick]

Stephan,

Those little bulkhead sections aft of the engines have virtually no structural value. Under Coast Guard requirements the engine bilge is to be closed from all other common bilges in order to contain oil from reaching a bilge pump. Do not include a limber hole aft, plug the other limber holes and build the bulkhead with only containment in mind. Epoxy and plywood will be fine. Coosa board and epoxy for the purists out there...

[Bob H.]

Stephan, Most of my structural bulkheads were made of Okume plywood coated with epoxy, and 1708. Splicing in a new patch piece may be as labor intensive as ripping out and making a new rear bulkead. Cutting and glassing the entire bulkead out of the boat on a flat horizontal surface is much easier. Tabbing the old and new plywood sections may give you grief down the road. Like chasing your tail. Fix one problem at a time do it to the best of your abilities and move on..BH

[Carl]

Stephan, Most of my structural bulkheads were made of Okume plywood coated with epoxy, and 1708. Splicing in a new patch piece may be as labor intensive as ripping out and making a new rear bulkead. Cutting and glassing the entire bulkead out of the boat on a flat horizontal surface is much easier. Tabbing the old and new plywood sections may give you grief down the road. Like chasing your tail. Fix one problem at a time do it to the best of your abilities and move on..BH

Stephan, Bob speaks the truth. I repaired mine several times though the years...took me awhile each time. Every go around looked worse then the last and fell apart quicker. Finally when I redid deck, I ripped it all out and made in one piece from marine Ply that I glassed and laminated an additional piece at top to give a bit more width for deck to sit.
I spent more time doing the half arsed repairs then it actually took to make and install the entire thing from scratch.