Thank you so much for the replies so far and the time it took to chime in (especially you carcrash and Jass). (BTW Car - you post led me to this informative reggie Fountain video... http://www.youtube.com/watch?v=M8Qzsf6aZpk )

I'm obviously on a crash learning course here and this is an incredibly helpful beginning.

A couple of newbie/ignorant questions:

Surface drives backing down - how does that work? Would seem squirrely.

Surface drives at slow (displacement) speeds?

Surface drives from a dead start (hook-up?).

Steps backing down?

I know the arguments for steps - what arguments am I going to field against steps.

Turbines are too thirsty, I believe. Customer would like 300 mile range. What are their burn rates and reliability like. I was in the Marines and they were always maintaining the turbines - always. I always wondered why so much as a turbine is pretty simple isn't it? Way less moving parts I always thought.

Mike Buck is working on 6 cylinder 650hp Marine diesels with 850hp models to come. Give him a call;

www.buckdiesel.com

Well if carcrash is a rocket scientist I would believe what he says. :D He's right, Fountains are the fastest V bottoms in the world.

I think the reason they were maintaining them was because they were in air units(correct) Turbines are simple, have a huge life span, also the power to weight is unbeatable..

John jr

You might also consider a beak on the bow...you could market as a 46'....

I think you should take a look at turbines. John Arruda at www.turbinemarine,com put a pair of his 1450hp turbines in an 18,000lb 51' Outerlimits V bottom and it's running over 130 with Merc 6 drives. He has solved a lot of problems with turbines in the Marine environment, especially exhaust heat with water-jacketed exhaust. One problem with turbines is they burn as much fuel at idle as they do at WOT.

Eliminator boats built a 12,500lb 43' V with staggered 480hp Cummins-Mercruiser diesels that is running close to 75mph. If that boat(Scarab) had the Fountain bottom it would run well over 80.

One way to wring more speed out of a diesel is multispeed transmissions. Weismann has developed transmissions from two to six speeds and they have also developed a Marine drive to handle the huge torque;

www.weismann.net

:D

blacklabmarine -

This is my advice take it or leave it - you already said you need diesel. This is most probably a goverment type application so anything other than off the shelf product can't even be considered.

Your building a big, heavy and wider(?) boat I guess.

Steps or not, your not going fast enough to make that much difference (people will argue that but any straight bottom can go 70 mph with ease)

Look at what Magnum has done, see what engines (Cat or Cummins) and drives (Arenson) they run and go from there - they make big heavy boats that go fast!

Trying to go do all kinds of things to copy the fiberglass builders will get you no where fast. Find an aluminium Cougar monohull - measure it, study it and copy it - it works, it goes fast, it's proven in a sea, etc, etc -

Just my 2 cents?

I actually got a quote on the Banks/Duramax 4 days ago. 17.5 K ea still dont know if they will work for me in my application though. Tuneable 350-550 hp.

Metal Bros Racing - Banks gave you a quote for $17,500 for a "tunable" Duramax that goes from 350 -550 Hp is that what you are saying?

Backing down: Just like anything else, the boat will slow down until you stop or give it more throttle.

Slow speeds: The boat will turn and steer like any other boat that is off plane

Dead Start: They will hook up and when the turbo's spool up the boat will take off.

Look at the Fountains you have been advised about. They to are running the Arnesons and there are no problems with the areas you asked about.