Pat, I like your attitude: everything's possible.

C-Spay, I suppose something like that could be done and it's been done for combined turbine and diesel propulsions but what would be the cost? Might as well go for Arnesons or #6s in that case.

Moreover, there is a question mark over the reliability and performance of such a trannie. It's complex and it would have a fair number of moving parts. Which means potential for trouble. Plus, how many horsepower would it cost to turn all of that?

So, it's possible but I am not sure it would be a definite answer to our problem. Our problem is to find a drive which is easily adaptable, reasonably cheap and reliable under approx. 800hp/800lb of torque. A splitter trannie is an option but not a direct solution to the problem.

Buzzi has been working on a trannie like that where he wants to hook up two turbines and two diesels on two output shafts, while being able to switch from diesels to turbines on the go and vary the % input from each mode of propulsion. Apparently, it's been a bit of a headache to say the least...

My buddy just put in two konrad stern drives with a Yanmar 440.

He said the konrad is the only commercially rated stern drives in the market if your intrested you should check them out.

C-spray,

We have made many types of boxes. I need to watch the everthing is possible. Some ways to limit the torque are to run hydro static or torque sensors on the driveline and throttle by wire. Sounds expensive. The last quote I had for torque shafts was $12,000 each.There are not too many cheap 1000hp motors either.

I think it is easier to make a propper drive.

We manufacture in the states, the price is high quality is good. If we go over seas, cost is low quality is hit and miss. My guys will not work for 19 cents a day. My competition builds parts overseas and I am expected to be competetive on price. I want to keep the jobs and knowhow here. The only thing that will bring the price down is numbers.

pat W

Wasn't IMCO working on a twin drive/single engine setup? I have seen something like this on drag boats.

Yes, IMCO was working on a trannie like that. I think I saw something about it in the Hot Boat mag. This was surely over a year ago. Haven't heard anything about it since. Anybody knows anything about it?

Pat, I think we agree on this one: it's very often better and cheaper to address the problem directly and what we need is a proper drive...

That twin drive was in Powerboat mag. last year.
If I remenber correctly it used straight cut gears to split the power to two outdrives so the power loss was very low. I'm thinking it was on a turbo big block used for the Catalina waterski race.

Mastry had a boat at the Miami Boat Show with a single Yanmar engine powering TWO drives.
I will try today to find the link to more info on this.

Super - Fabio's layout, with four inputs and two outputs does sound like a nightmare.... I'm thinking one in and two out with no shifting. That would be handled by the drives. Again, the torque reduction (overdrive) could be incorporated right into this primary box.

Pat - What about a simple clutch pack preloaded to a given breakway point? A simple set of input/output shaft speed sensors would detect excessive slip and cut back on the power.

Wouldn't a single 1000 hp diesel cost less to purchase and install that a pair of 500 hp diesels? Sooo much less complexity...

What is the current torque capacity of your two drives?

Could you just picture a large poker run like the NY run the flag drops for the start everyone guns the throttles Bam one big giant black cloud hangs over the harbor the wackos would be on us like stink on ****!!

Actually, I just read an article in BoatUS about the new marine diesels that will be required in 2006, and the new Volvo's in particular. They sound like well-behaved engines.