What's the "Final Word" on Raising Stringer Height in 20 SF

[GoodChance]

I have a 1971 20 SF Seacraft in the barn right now getting a full restoration. Liner is out (and will stay out), transom was raised to 25", balsa coring was installed on the hull sides to increase rigidity. The motor will be a Mercury 115 CT (360lbs) or a Suzuki DF115/140. Of course, the motor will be hung on the transom. I'll be mimicking many of the features of BillyTheKid's 20 SF restoration in 2014.

I purchased a sheet of dyvinicell to use as material for elevating the stringers. What is the final word on how high the stringers need to be raised to have a relatively dry deck in offshore conditions? I've heard everything from 2" to 4" but I'm not sure if these reports are including the new deck. My deck will be 1" Nidacore.

How high do the stringers need to be elevated?

As many of you now, this decision is often difficult because the SF doesn't have a lot of freeboard with an elevated deck.

[JohnC]

I am curious about this too. I have read some rebuild threads and I recall reading about raising the deck 2" and 4" but I cannot say which thread I found this in. I measured a friends 1976 SF - I think this model year would have had a higher deck from the factory. This one is not self-bailing but that has less to do with the deck height and more to do with having a 250 Optimax on an aluminum bracket.
It would be nice to get comparative numbers from someone here who raised their deck.

[GoodChance]

I want to update this thread so others can learn from my research obtained both here on CSC, on THT as well as some text messages.

I finally settled on raising the stringers 2.5" with the Nidacore floor adding another 1" above the stringer elevation. All said and told, this will put the new floor 3.5" above the historic waterline of this hull while at rest.

At current, the stringer have been raised and the divinycell. The 2.5" sections of divinycell were bonded to the old stringers with Arjay 4001 adhesive putty. As I type this, it is drying. Later I will round the edges and wrap in CSM and 1708 biaxial fiberglass and adhere to the old stringers.

In the course of two weeks and since obtaining the 1971 SeaCraft SF, the hull has been stripped of the liner and the old transom; the cap has been removed. A new transom has been installed and glassed into place, balsa coring installed on the sides of the hull (above the waterline only) and stringers raised.

Thanks to everyone for your help especially Ole (Parker Yachts), Robert at Calcutta, Parrott, Tunatango (BillyTheKid), Aaron T. and Grady

[Mark]

Originally Posted by GoodChance

All said and told, this will put the new floor 3.5" above the historic waterline of this hull while at rest.

You'll be glad you did that….and you won't feel like you overdid it either.