The previous owner had the entire transom replaced and used marine grade wood. I say spend the time and money to do it right the first time, otherwise you will be doing not once, but twice!

Agreed that is why I am looking for alternatives. New OEM's seems to be using composites to replace items formally made of wood glassed in or otherwise. I'm talking with some buoyancy engineers tomorrow(I would typically go lowtech to fix old school but since I have access to these guys they'll pull a wireframe and run it through the sim).

“I haven’t failed. I’ve just found 10,000 ways that won’t work.” - Thomas Edison

Don't be afraid of a wood transom. Your first one lasted 25 years. If done properly a new one will last another 25 easy. Have you checked your stringers yet? Usually the old boats all had the super-structure installed then wrapped with glass, so if you get one area wet the water begins migrating throughout the whole boat.

yep, i actually prefer wood transoms over composite (for performance boats). I use Coosa regularly for superstructure and stuff but am just not sold on its ability to handle high compressive loads over time. If you absolutely had to have a composite transom use three layers of half inch to build it rather then a single piece of two inch.

If your repair turns out to be any more then a square foot or so just do the whole transom, general rule of thumb is you can only passively detect about a fourth of the actual stuff that will need attention once you start cutting. I own a Scarab III and am very familiar with the layout. You are most likely looking at stingers as well once you dig into it. The center stringer on these boats has exposed wood on the bottom at both ends and this area acts like a sponge over the years.

The key to keeping wood alive is total encapsulation of the final product. When i set new transoms i make a very large "mouse hole" around the drain plug and make that area 100% glass where the hole gets driller. All cutouts for drives and exhaust are cut slightly oversize and a layer of glass is placed on the exposed edge. Water drainage holes are also cut slightly larger and i meticulously place a layer of fiberglass like a tube in each hole. The holes for the transom assembly bolts are treated with Cuprinol (the green stuff they use to treat lumber) and sealed with 4200 when it goes together. Most of this sounds very time consuming but really is only a few hours at the tail end of finishing out a transom repair and far less time then doing it again a few years down the road. Its really just a maker of taking your time and thinking ahead.

Not sure what a buoyancy engineer is gonna tell you . . . or much less any engineer that has never laid a transom is gonna tell you . . . . (btw I am a degree'd ME)

Hey Dave/Deezy I am leaning back to wood; I haven't done any cutting just some drilling and only found wet wood around the SB trim tab and sadly the area is larger than a Sqft. I'll check on the stringers as well; but probably won't see much until I pull the whole thing apart.

So it may be time to take a couple of weeks off and knock it out. Dave to your question; BE's which are ME's at my job have a tank that can simulate pressure and surface tension/stress on the area. Unfortunately I'm also a credentialed AE/EEIt really does get us in trouble because we know what we should do; but our pockets tell us to try cost effective practical things). I'll check back in when I get home this weekend and send an update.

I am in the middle of doing the transom on my 89 scarab sport. When they built my boat the stringer tails where butted up against the wood transom so they had wood on wood contact. Needless to say they both rotted together! I had rot spots at the trim tabs, top of the transom where the outboards hang, at the drain plug and where the outboards where mounted. The rot was partly the result of improper mounting (drilling and not sealing the holes properly) and bad fiberglass work at the factory (the fiberglass mat was not completely sealed at the end of the stringers). If you are going to do a complete transom then you will be able to see what is rotten when you remove the glass but it surpirsed me how many little 8" x8" areas of rot I had.

Found a fairly decent article (http://www.rotdoctor.com/glass/GLrotrepair.html) and could envision what you found at the stringers after reading.

So what is this trim tab pull test? Ive never heard of this.

Its pretty basic really but it works best with large tabs like 280's. Just stand on the tips of 'em and rock, have someone gunsight from the side if you cant get a good look. Works with drives as well. Because most of these older boats are very heavy wet lay ups the movement, if any, will be subtle so you really have to pull and push hard. Lifting up on them is also a good idea. Older Scarabs were known to have issues at the corners where the tabs are mounted and, truth be told, this KV appeared fine and tested reasonably well till i really rocked on it. I could see just a minor flex above the tab and after i got out the cutter all i found was a hay field lol.

looks familliar, my buddy just cut out his entire transom, now we gonna put the notch in it!!! yippie!!