20 foot SC stringer question ???

[RobertElmore]

Is the stringer placement the same on the I/O and the outboard models ? I am building a sweet 302 roller motor. I was going to put it is a 18 donzi. But as a lover of SeaCraft I can not bring myself to build a diferent breed of boat. I had a 2 and now I have a 23. I want to find a 20 footer and make a play toy. So any info on the stringer payout would be great. I know the transom will have to be changed but that is OK I love the totle redo for this on. I plan to push 425 HP out of the 302 so I will have to do stringer work any way. TY Robert( LongAshes )

[workinpr0gress]

Mine has the two box stringers. They are the same except there is a wood engine bed sistered to the inside of each stringer for the v8 that used to be in it.

[Blue_Heron]

425 HP in a Seacraft 20? The Potter 20s will do 55+ with 225 HP. 425 HP just sounds like a creative way to commit suicide. I've touched 50 mph in my 20, but that's all she's got with a 200. But I understand Seacraft hulls start to chine walk at around 60. Here's a post from Fr. Frank I found from about a year and a half ago:

You have a point, here. But SeaCrafts CAN be made to run over 60, and I have seen a 20' SeaCraft with a slightly modified hull approach (but not quite reach) 70 mph.

I didn't do the hull work, but I did tune the rig on a 20' SF with a 240 hp. Merc Bridgeport on a hydraulic jackplate. We ended up running a custom prop from 2nd Effort in Lk. Hamilton, FL. The boat was REALLY, REALLY Squirrelly from about 55 to 62-63, and then settled down until reaching 68, which was WOT. Without trim tabs and the hull mod, there is no way it could have been pushed past 62.

The hull mod was done by Rybovich/Spencer in WPB, and included a flat planing pad on the rearmost 5'-6' of the center V, much like the early Steve Stepp 22' Velocity hulls. With a similar modification, I believe a 20' or 23' can easily be pushed past 70 mph with modern outboards.

I think your hull, Steve, can be pushed to near 80 mph with a similar mod, and a change in drive and engine, ..say to Mercruiser EU662-SCI.

So you may want to consider some hull mods before you stick that rabid small block in a 20.
Dave

[RobertElmore]

I had the same concern with the hull. The Seacraft Hulls ride different than a donzi hull. The Seacraft on a plane rides high in the water. I will have to do some reshearch on the hull mods. This is great info TY