Boat porn of a 25 Seafari beasty

[Bigshrimpin]

This thread keeps getting better and better!!! Yikes! Steven - I didn't realize who I was talking too . . . and I understand if this information is proprietary. I was just curious.

Forgive me here . . . but isn't 37% LCG way far forward for a powerboat?

[doug7488]

That's alright - No offense taken!
I do enjoy my boat, although maybe not as much as I'd like to!
Maybe Strick could breath some life into a dead horse?

[1bayouboy]

Interesting about the ballast system in this boat.... web page

[bigfluke]

We tested the Seafari at weights from 4200 to 7400 lbs and with lcg's from 27% to 37% so handling isssues happened under many different circumstances. Our first tests were to develop a novel drivetrain with a 480 hp Yanmar and Weismann surface drive and we achieved 45+ knots @ 7400lbs. Current test configuration is with 300 hp Yamaha outboard on a Porta bracket. Our focus has been to move lcg as far forward as possible to improve pitch behavior without compromising following sea handling. Our hydrodynamic tricks to the hull bottom have been focused at reducing the increased drag which comes with a forward lcg. We have already yielded a 3+ knot improvement in speed and expect to see +5 knots on the next experiment. The info that Moesly had intended a ballast system makes a lot of sense from what we've experienced in running the boat with lower and further forward lcg. The basic boat has outstanding seakindliness at all headings when weight and lcg are dialed in. When we finish all of our research we expect to see a 15% improvement in speed/power and elimination of the handling problems that are inherent in many narow, deep-v hulls with fine entry. I consider Moesly along with Hunt, Hickman and Lorne Campbell to be creative innovators who have made major contributions to planing hull technology while achieving balanced and producible designs. I am delighted to have learned that Moesly planned an integrated ballast system which would have eliminated the sub-par performance issues with the Seafari. I'm sure if he had continued the development of this boat it would have truly been an outstanding performer and benchmark for its size.

[NoBones]

Current test configuration is with 300 hp Yamaha outboard on a Porta bracket.

Scott Porta's shop is in Edgewater FL. close to Everglades Boat and Boston Whaler.
He has a heck of a shop and does nice work. Scott has always
been innovative in the marine industry.
You would be surprised at the amount of boat manufactures
in Florida alone, currently there are 556.
Alot goes on here that few even realize.
I love being a Florida Cracker.....

See ya, Ken

[glow]

Excuse me for my ignorance. What is lcg, lower center of gravity? Thanks, Greg

[Bigshrimpin]

Longitudinal Center of Gravity. The lower the percetage . . . the further forward the point is towards the bow.

[mbo_1971]

what is an average for us non technical types? 37% is an interesting number, but is it 37 vs 75 or 37 vs 45? Thanks.....

[Bigshrimpin]

I'm no boat designer, but I've read that most Deep V hulls have LCG well past mid ship like 60% + , but I don't really know.

I can't remember if there was a difference b/w lcg and LCG? I think they have different meanings. Where's the BigFluke when you need him

[bigfluke]

LCG is the Longitudinal Center of Gravity. We measure it in feet from the transom heel (bottom of transom at the keel)to the center of gravity. When represented as a %, it is the LCG measured length as described compared to the static wetted length of the boat. The Seacraft 25 has a wetted length of 22'at full load displacement. Thus, the 37% LCG at a heavy displacement I described equates to 7.9' from the transom heel. We chose this location for the trials because it is where the static trim of the boat is 0 and generally results in better seakeeping, especially in head seas. A more typical LCG for an average planing boat of this size is about 33% and very high speed boats will have a LCG of 30% or less.