Wow. Poor guy. I'd have any sort of transmission strictly on switches I could control. But 6 is a bit much to handle. I've often thought you could run a manual valve body turboglide with no TC in a boat, not sure if that's been tried.

The big issue with diesels in fast boats is a low "turn down ratio". The ratio of the max speed vs the idle speed. Gas engines are almost double that of a diesel since the idle speed isn't much higher but the max rpm is much higher. I think that's part of why roots and screw blowers are also great in boats, you can run a milder cam to idle well and then run higher engine speeds due to the blower keeping it breathing.

The need for multi speed transmissions and heavy engines are detriment to Diesel engines in planing hills that are very sensitive to weight.

The economy and on the water fuel price can't be beat though, if you're budget minded.

I know what he was after with the 6spd. Trying to get a 12k lb single engine straight bottom boat to run 60's with a diesel isn't your common build. But his other boat is a big 100mph + single turbine cat he built long before those ever became popular. Just ask Rik on here about him, Dave has been doing crazy boat rigging chit for a long time. But he recently decided that fishing might be a more relaxing hobby... lol

When I first talked to him the 6spd setup was all ready in the boat. I would have never went with that funky no converter Allison deal. But the CA boys talked him into it before we met. Best the boat ever ran was when you locked it in 4th gear all the time. I'm sure it can be tamed, but from 3000 miles away all I could do is read data logs and give advice. And his logs were often very nasty looking. Like he was driving some 800hp truck with bald tires on a icy road. TCM would think the boat was running 120mph, then drop off to 40 soon as that big 18" prop hooked up. When it was actually allowed to shift into 5/6 overdrive, it would cut power or throw limp mode to the engine due to clutch slippage. He even put a torque converter back into the mix on this last build.. Not worth all the hassle, that was our final conclusion about the marinized Allison transmission.

On a side note, he recently donated a spare engine for testing of monotherm pistons in the Dmax. So hopefully all his time, effort, and $ invested will lead to a good outcome for everyone else. These engines are still lighter and will spin more R's than about any other diesel out there. And while many have pushed them well into the 1500hp plus range, that's for like 3 - 8 seconds at a time. Big difference between drag racing and life in a boat.

It's a shame the Dmax's didn't work out for him. Hopefully something good will come out of the monotherm effort. Mine will be hooked to a Konrad drive on a 9-10000# boat and hope for a 30 mph cruise at about 2800r. Will need to run contentious for 1-3 hours at the time at this speed, stock.
Thanks for the info

Your welcome. And I hope some of this info helps with your build. As long as there is sufficient cooling, especially of air and oil, it should run happily at 2800r all day long.

Hi,

Great thread and more or less a complete "how to" for a marinisation but after the TPS was descriped i was hoping the thread would get "back on track" and get more into the how to on the electrical side of things like ECM and harness etc:-)

That being said, i see a new cool project are keeping you busy:-) that will be a bad ass build with 900+.

rgds Allan

Tks Allen. Have a couple more engine builds underway at different stages right now. One has a stock truck harness that was previously used in a boat, while the 900's are getting custom wired from sensors to ECM. So I'll be back on track with updates this next week.

Marine Diesel in Sweden offers a marinized package that is certified using the Duramax 6.6L.
They offer 12V and 24V. I have the 24V version, but unless you are driving a big boat with lots of other 24V requirements, I would stick to 12V.
I like the fact that their alternators are 145amps so you can drive a bank of 220AH batteries and use mastervolt Sine Ultra inverters for your 110VAC / 220VAC systems to drive airconditioning and other household paraphernalia.
They have a U.S. Agent as well.
They are very quiet engines but I would suggest looking at their raw water cooling system ... i.e. either the possibility of draining them or running fresh water through it.
They are great engines!

Welcome to the forum. Please share some details on your boat setup? What type of drive ya running?

this is the US site https://www.performancediesel.com/pr...marine-diesel/