Just got home from the Miami International Boat Show.
"Hustler" had a 39' deep vee with twin QSB 480's.
Normally based on the 5.9, these 2 were 6.7's.
Same 480 HP but I was told more to come!
BTW, top end was 100 MPH.
Cruise was 95!!!
Imagine 95 for a cruising speed,
and at 4 times the mileage of the gas boats.

I want one. No really, I want one as I have a project(a 30' deep vee)
in my garage that needs a motor/drive combo to finish it.

 

Go for it! Better fuel economy, more torque, and no gasoline fumes to worry about. Ya gotta love those diesels! I do have to wonder how they convinced the electronics that the engines were still in a truck!?

 

I wonder if those are surface drive props? Did you see them?

Also, I'm impressed that they can rate the Cummins for 480 HP in a boat. It's a constant heavy load. That is some serious power for continuous duty.

 

People are pulling in the neighborhood of 1000+ HP out of these engines. Granted, the reliability suffers a tad, but my point is that a properly cooled 6.7 would probably not have a problem with 480. Factor in too, a boat isn't subject to the smog testing, so you don't have to dump oxygen depleted air mixed with soot right into your intake.

 

This boat had SpeedMaster drives and staggered motors. Not sure if it was set up for surface piercing, likely it was. It is an option with SpeedMasters.

480 HP has been avail. on the 5.9 for a few years. This is first use of the 6.7 in a marine application. I was told they stuck with 480 as a starting point.

The QSB 480 has a high output rating of 480 HP @ 3400 RPM. But, you can run 3200 RPM all day, but this continuous rating is also down to 400 HP.It's common to see marine diesels run at this lower rating all day.

 

Pulling 1000 HP for a couple seconds on a dyno has nothing to do with a steady hard load for hours on end in a boat. Cooling the engine is not as hard as cooling the pistons and the exhaust valves. It's not about smog, it's about reliability under heavy extended load.

I'm impressed.

 

That is very impessive for a small bore engine. I'd like to hear it at full load.

 

I just saw this on the Cummins site about operating requirements for the 5.9 with 480HP.


* Cummins Full Throttle Requirements: • Engine achieves or exceeds rated rpm at full throttle under any steady operating condition • Engines in variable displacement boats (such as pushboats, tugboats, net draggers, etc.) achieve no less than 100 rpm below
rated speed at full throttle during a dead push or bollard pull • Engine achieves or exceeds rated rpm when accelerating from idle to full throttle
Rated Conditions: Ratings are based upon ISO 15550 reference conditions; air pressure of 100 kPa [29.612 in Hg], air temperature 25deg. C [77 deg. F] and 30% relative humidy. Power is in accordance with IMCI procedure. Member NMMA. Unless otherwise specified, tolerance on all values is +/-5%.
Full Throttle curve represents power at the crankshaft for mature gross engine performance corrected in accordance with ISO 15550. Propeller Curve represents approximate power demand from a typical propeller. Propeller Shaft Power is approximately 3% less than rated crankshaft power after typical reverse/reduction gear losses and may vary depending on the type of gear or propulsion system used.
Fuel Consumption is based on fuel of 35 deg. API gravity at 16 deg C [60 deg. F] having LHV of 42,780 kj/kg [18390 Btu/lb] and weighing 838.9 g/liter [7.001 lb/U.S. gal].
High Output (HO): Intended for use in variable load applications where full power is limited to one hour out of every eight hours of operation. Also, reduced power must be at or below 300 rpm of the maximum rated rpm. This power rating is for pleasure/non-revenue generating applications that operate 500 hours per year or less.

 

We had differnt diesels in the Coast Guard from Detroit Diesels to MTU's. They are kind of what gave the bite if the diesel bug. We had them for everything from propulsion to various generators.