1988 Sea Ray Seville 21 Cuddy sole & transom rebuild

[NWVintage]

Ahoy!

As the title suggests, I have a 1988 Seville 21CC and I discovered some rot. Well, I knew about most of it but I've become more concerned about it. It has some weird patterns to it - like it's in some places but not in others where I'd expect it - so, I have some questions about where these boats have a tendency to rot/collect water and where I should look to determine whether I can get this season out of it safely and dig in this fall.

First, where are the characteristic places that these things rot? There's some softness and slight separation around the bottom 1/4 of the transom hole but it it'll be fine for this year - plenty of good wood. What has started to concern me is that there is pretty significant rot all along the edge of the sole where the gas tank cover screws in. In fact, that whole edge along the gas tank is pretty rotten and the glass was done VERY poorly along this whole edge. I wasn't too concerned about that until I found out that the stringers are apparently wood...? Why would they do that in the late 80's ?!! I had assumed that a brand with a rep like Sea Ray would have been 90% glass by that point (my '78 GlasPly has glass/foam stringers...). Anyway, I also tore out that stupid cooler-under-the-seat thing because I put a wrench through it while I was unbolting the starboard engine mount and found out how unintelligently that was constructed as well and the floor is pretty rotten under there as well. Another weird thing I found is that there's full foam under the sole under the cooler thing but there doesn't appear to be any in front of the bulkhead that's just aft of the gas tank - the sole has separated enough that I can slip a hand under there and it appears to be hollow...?

I'm concerned about the overall structural integrity of the boat.

What are the stringers made out of? How are they arranged? What density foam was used? Why the heck is wood involved? How did Sea Ray get such a great rep with such cut-corner fiberglass work?

I watched some of a rebuild vlog the other day of a 1995 and he had his out of all plywood. Sort of a stringer/bulkhead matrix of 1/2" plywood, then plywood over the top, foam through holes, glass over top. Here's the channel: https://www.youtube.com/channel/UCqz13HCBRHihm2L883-7UlA. If that's all they are, I'll likely just dig in. But also, if that's all they are, isn't the glass alone likely structural support enough even if the wood is 40% rotten?

Before, I get this response - yes, I've started my research on here and I'm aware that these questions are all likely answered elsewhere. However, links to some of the better threads would be great and I intend to keep this thread going throughout the process. I'll also answer my own questions as I find them. And I'll post photos in a bit. I

I'd put a link here to my build thread from my last boat but the boat was from a smaller manufacturer and someone allowed us to lose the domain where the forum was hosted for a short time and all was lost...

 

[Chris1956]

I had a '88 19 foot SR Sorrento. What I found was that the construction of the boat was not consistent. Here are some examples of what I found.

The stern portion of the deck was just resin, as if the chop gun ran out of chopped fiberglass. This had rotted out. The bow to midships portion of the deck was much heavier, and I never had any issue with it.

The bolts for the seats were embedded in some hardwood blocks, under the deck. This hardwood sat in pockets in fiberglass, but the pockets had filled with water and rotted them out. There was a layer of glass over the foam, and under the deck...go figure.

Anywhere the builders cut thru the wood structure, was never treated. For example, the ski well cover sat on the plywood deck, that had been cut to size. The edges of the plywood were raw and rotted. This caused the sides of the ski well to rot and eventually the bottom of the ski well to delaminate.

The keel of the boat under the ski well (between the split windshield, was scribed plywood, stapled to the plywood bottom of the ski well. The staples had rusted away and the "keel" fell over, allowing the bottom of the hull to deform.

I also believe (cannot prove) that some parts of the hull were not foamed completely. I had a crack develop in the hull, right on a strake. That should have been one of the stronger parts of the hull. I repaired the crack from the inside and engineered a new stringer to support it and foamed it. The stingers are wood, BTW.

The side panels were made of multiple odd shaped pieces of wood and stapled end-to-end. The vinyl held them together until they rotted.

I always suspected my boat was made on a Friday (or Monday), as was of exceptionally poor quality. Maybe not?

 

[Scott Danforth]

its a 33 year old boat with a 15 year design life

nearly everyone in the 80's had shoddy workmanship. the goal was to get boats out the factory door as cheaply as possible. your boat is nothing special, its just like nearly every other 80's boat. its better than a bayliner

they (nearly all recreational boat builders) use wood because wood is cheap and lasts longer than the 15 year design life with even the worst of maintenance

they use all the scraps of wood and staple them together like Chris mentioned because it reduces waste and keeps the cost down

the only thing you can do is build a cradle, de-rig the boat and dig in.

look at link 14 in the DIY stickies