KamaII

[Bigshrimpin]

Originally Posted by Islandtrader

Funny how small this 21 looks...

Terry - I'm pretty sure it's #40 John Steinback rigged as a single outboard . . . last 2 pages of the race results. Came in #1 in single outboard division for a few races.

[gofastsandman]

Originally Posted by Islandtrader

Funny how small this 21 looks...

Largest 21 I`ve ever seen. I was out of sight inside. Thank you.

Cheers,
GFS

[strick]

Conner, I never asked him about the boat with the big chines. On the boat with the sponsoons he said that he was trying to create more lateral stability and correct the heeling to port side which my boat does do a little as well. Here is one of his e mails addressing this.


"The attached SeaCraft 25' picture shows the boat before modifications. We have been tricking it out with outboard sponson additions (ama in Hawaiian) to improve stability and are presently installing engines and fuel layout which gives an extremely forward LCG to improve seakeeping via lower running trim and higher moment of inertia. With this LCG you don't get much bow rise to get on plane. We have some patent pending tricks to the running hull bottom to provide increased forebody lift and ventilation to increase efficiency via better trim and less wetted area to offset the drag that is the negative of a such a forward LCG. Bottom line is that with a LCG of 37% of waterline length, we get the same speed as one set up race boat style at 27% LCG. Design lightship is 5300# and max displacement 7500#. While we have played with other hulls that have as good a head sea ride it is an unbelievable hull that even at these full load displacements we haven't been able to stuff the boat running downsea.

We used the amas instead of large trim tabs to achieve transverse stability at rest as well as running. Also, the amas stopped the chine walking and port heeling we were getting with all the single engine 25's we've tested. The other advantage of our final layout of pushing the engines and fuel so far forward is the clear aft deck area for fishing, coolers and other payload. The engine box serves to give us a raised command bridge."

strick

[McGillicuddy]

I remember shipping that red 25 to Hono, 4 maybe 5 years back "Avalon" from NY, I think...the same week I looked at a 24' Airslot out of curiosity. I thought what what would their respective designers talk about over a few adult beverages?

Clearly Big fluke had already considered their merits...

Big, was Steinbacks blue "40" a 21'? and would he have been running a single 140 hp tower of power?

Strick, is Chet kin folk? Interesting note from Big fluke.

[cdavisdb]

Interesting stuff, Strick. A lot between the lines when I think about mine.

I never noticed either chine walk or port lean, but mine is a duoprop that should eliminate the lean and I almost never run fast enough to chine walk. I wonder if those two are connected? It does want to porpoise a bit when light, as bigfluke noted somewhere else.

Love the ama idea for stability at rest, but how much drag does it add? Should be quite a bit, but with his engine hp, who cares.

I wonder how our single V8s compare with his calculations of CG. CG going from 27 to 37 should change the CG point about 2 feet (i think). Going from a double six to a single v8 should be about 6-700 lbs less in the stern, moving the CG higher by a substantial degree, but I don't know how to do the calculation. Blue Heron, any help? I know mine doesn't have much bow rise to get on plane, especially when loaded heavy.

Big Flukes boat is HEAVY, I figure mine light is at something like 1000 lbs lighter than his and 7500 lb is a huge load. He must have a whole bunch of those pig weights.

[Normagain]

Originally Posted by McGillicuddy

I remember shipping that red 25 to Hono, 4 maybe 5 years back "Avalon" from NY, I think...the same week I looked at a 24' Airslot out of curiosity. I thought what what would their respective designers talk about over a few adult beverages?

Clearly Big fluke had already considered their merits...

Big, was Steinbacks blue "40" a 21'? and would he have been running a single 140 hp tower of power?

Strick, is Chet kin folk? Interesting note from Big fluke.

That's interesting, I looked at a 24' Airslot just before buying my 20' SF. It had a big tower on it and the guy was asking for about what the tower was worth. If I had a few more feet in my parking space, I would probably wound up with that and put a bracket on it. I'd be in it even more deep than I already am however.

[FishStretcher]

Is anyone in touch with BigFluke anymore? The air cushion amas is an interesting idea.

[FishStretcher]

Is there more than the Amas/ sponsons? The video is now is 720P and I got two or 3 good screen grabs. I think those are alignment/ registration marks for installation or video. Unless they are lateral steps??

[Blue_Heron]

Originally Posted by FishStretcher

Is there more than the Amas/ sponsons?

Note the spray rail that morphs into a lifting strake as it transitions aft. It sheds whisker spray, reducing drag, and provides more lift to support the forward CG he was running. Look at the beginning of the video when he's in displacement mode. The boat is loaded down with a CG pretty far forward.

[Bigshrimpin]

It's interesting to see BigFlukes 25 mods . . . I wonder if those black marks might be showing LCG?