Marinette Boat Forum

Hello,

I have all but convinced myself to replace my tired old 360s with a pair of Cummins 6BT 210s. I plan to couple these with ZF 63As 1.2:1, run my 1.25" shafts with a set of 16X21 wheels (and adjust from there). I figured the boat to be loaded up around 13,000lbs The cummins 210s make that power at 2600 RPM. I believe I am aware of all the little things that have to change for this to work. And yes, I know it is going to be quite pricey.

I would like to hear feedback from you experienced boaters the know the Marinette well. I am hoping that this will give me a fuel efficient setup. I am hoping not to loose to much speed. I wonder how the boat will handle with the extra weight? Just in case you are wondering why I do not mind putting the money into this boat....its because it is about the largest boat that I can trailer with a 1Ton pickup. I don't move it around alot, but i trailer-ed it on two expeditions last year (great lakes) when I knew I did not have the time or the $$$ to make the trip from the slip. Yes, i pull permits! Hope to hear from you all soon!

P.S. I would be glad to hear suggestions/arguments regarding the possibility of fuel injected gasoline engines if efficiency could be close or better. I have not spend much time researching this side of things. This would of course take away the possibility of running some of my neighbor's homemade bio-diesel which can be quite cheap.

Hello. First the Cummins is a very good engine. Butt for a 32 I think it would be under powered, for full "speed". It will not have the "speed" it has now. With good 360's and everything right and clean that boat should be close to 40 mph. You can't add weight, and drop HP and maintain the same speed. I would say with the Cummins it would top out at 25 maybe 30mph. If you are planning to run slower than it would be more efficient. I also think you will need 1.5 trans. I think you should do some more research first. How many hours do you plan to run a season? Rebuilding a pair of 360's would be cheep compared to diesels. Joe

I would love to have diesels but just couldn't justify it for myself. First thing is make sure you have room for the Cummins. I have one in a truck, I like them and it would have been my first choice. I think you might find the Cummins is taller and may be a problem. Just a warning. Otherwise with the higher torque you will get by with less horsepower. I would put plastic drivesavers in to help smooth out the power from the engine. Good for other reasons too. Just shop around, found them for sale for a lot less than that prop shop. You will never pay for the conversion in fuel savings, but if you do the work yourself and keep the costs down I think you will be happy with it. Good luck with it and keep us posted, Ed

A few things to consider going with diesels:

1. They are LOUD!

2. You'll need a return path for the fuel, so the tanks will need to have another fitting welded to them.

3. They make far more low speed torque, so you'd better have the 1 1/4 inch prop shafts.

4. Due to the above, you'll need a LOT more pitch on your props.

5. They will weigh more, which will make the boat aft heavier (correctable with trim tabs).

Not sure I'd go that way since the 360s are damn fine engines and very cheap to replace with rebuilt long blocks--even cheaper than Chevies!

Jeff

It would be way cool to have a 32 with a pair of Cummins. I'd be asking myself if I was going to be running the boat enough to justify diesel. Given the costs of conversion (and around here the cost of diesel fuel is higher) you have to consider whether you're actually saving. If you're running a lot (like say a commercial fisherman), then the diesels are worth it. If you're just running on weekends, you'd be ahead financially even if you sprung for crate engines. But if what you really want is a 32 with diesel power. . .

Good luck and let us know how it goes.

Joe

Good point. Running diesels a LOT keeps them in god shape; running them just now and then causes $$$ trouble. Just ask diesel mechanics who work on "rich people's" yachts (some that have only 2 hours running time per year--when the mechanics change the oil). The owners either haven't the time of ability to run their own boats!

Jeff

PS: Heard this from several yacht brokers.

While diesels would be awesome, I agree that you would have to run the boat for many many hours to offset the cost. I have seen a number of re-power projects using new gas blocks with much success. A friend re-powered with new 350s about 6 years ago. Overall improvement in efficiency and a real sweet new ride.

Not to change the subject, but could you share your trailering set-up. I have a 88 fisherman and would appreciate your experience with towing.

Thanks

Don't ignore the NOISE factor. No one will be able to stand being in the cabin with them running at speed. Okay, so maybe you're up top, but some poor soul is sure to be stuck 'downstairs'.

Jeff

My Diesels are not as loud as my buddy's 32 with gas engines. I have the varitone mufflers.
Roger

I'm not talking about exhaust noise; I'm talking the usual racket diesels make from combustion. A boat DESIGNED for diesels will have massive sound insulation, where a boat converted to diesels will not.

Others have gone that route with Marinettes and been horrified by the racket.

Jeff