UNSANE

Just been reading the other thread about diesels and picked up the Feb issue. They're using the Duramax engine that Habana Joe mentioned in the other thread. They're using it as a test engine for IMCO's new SCX drive and this boat, on its rev limiter, hit 77 mph. They claim they're getting 7-8 mpg!!! (I'm assuming that's cruise speeds and guessing mid to high 50's for speed but they didn't specify since the article was more about the outdrive.) The boat will be at the LA boat show and they're working on a deck boat next.

So.........would you????? I think I would. With my cut down windshield, all I hear is wind noise anyways, so wouldn't miss the roar of a 525. Can't wait until they strap this into a bigger boat!

Michael1

My BS meter just went off the scale. If they are getting that kind of mileage, it is at an idle. They are not going to get 2 times the mileage of a gasoline engine. I think we need an independent test. A 20' Baja only gets 3.75 mpg at 39 mph with its little 350 (boattest.com), and the heavier Nordic 21' with a heavier diesel engine that may be 30% more fuel efficient is somehow getting a 100% increase in mileage. Uh-huh.

I think this pretty much shows you can't trust the manufacturers for any diesel fuel economy claims.

Michael

HabanaJoe

I won't speculate about MPG, if the mag says it, it might be true, but here are some questions.

The diesel with that drive much cost double (I'm guessing at OEM level) what a Merc package does to attain the same speed?

If the ecomony is 4 MPG more than gas at cruise and both fuels are the same price $4/gal and let's say the package cost $15,000 more than a Merc you would have to travel roughly 15,000 miles additional miles at a 50 mph cruise to equal the price difference of the diesel - that's 300 hours at cruise speed - is that right?

If so, why ever bother with a diesel in a small boat?

I think that's point I keep trying to make - that's why all the diesel projects get canned for smaller boats - it makes no sense.

320es

Don't get me wrong...Diesels are great but nothing like the sound of a healthy big block in a boat.

tblrklakemo

I agree 100%

ZBODaytona

OH i don't know, I like they way an unrestricted v8 diesel such as the durmax or 6.0 sound. Not the same as a nice BB..but it does sound good.

RHC

The story was about the Drive ,, and I call BS on the whole test!! an Alpha would hold up on a 21 ft boat that is light weight ,,, put those engines in a 10000lb boat and run it wide open ,, then tell us how good the drives are and what kind of fuel your burning !
It was a waste of good paper space !

RHC

Liquid Liability

[QUOTE=HabanaJoe;2434606]If the ecomony is 4 MPG more than gas at cruise and both fuels are the same price $4/gal and let's say the package cost $15,000 more than a Merc you would have to travel roughly 15,000 miles additional miles at a 50 mph cruise to equal the price difference of the diesel - that's 300 hours at cruise speed - is that right?

If so, why ever bother with a diesel in a small boat?


A perfomance diesel in a small boat makes perfect sense when you consider they are getting similar performance as a 500efi or 525 in that size boat and you take into account that the performance diesel's durability will take you through a minimum of one complete rebuild of the big block at cost of $8000-$15000.

Your total return on investment in reduced maintenance, rebuild costs, down time (ie. boat at the shop and not on the water) and decreased fuel consumption make the initial added cost of a performance diesel package a very attractive option to consider once it is fully tested and dialed in. IMO

Liquid Liability

EXACTLY...especially with the turbo making 30+ lbs of boost!

baywatch

In the March issue of Powerboat that I got yesterday they have 39 nor tech that they tested with a pair of 480hp yanmars hooked through the ASD-8 drives.

Where the options are listed it lists the yanmar upgrade @ $50,000 from the base power package (merc 525efi's). It doesn't mention anything about the price on the Arnesons. If 50k is really the charge to go to yanmars and asd-8's that doesn't seem bad at all to me.

In the fuel economy section they list: 40mph=2.6mpg 50mph=2.5mpg 60mph=1.9mpg 70mph=2mpg 80mph=1.9mpg
Top speed was 80mph @ 3,475rpms

This is a good example of what I would be looking for in a diesel application. I don't need to go 100mph but I would love to get 2mpg @ 70 mph and 2.5gph @50mph. Most of my running is done between 45-65mph and anything I could do to improve reliability, maintenance intervals and fuel economy I would be all for.

My boat is an old apache 36' v bottom and I would guess it to be much less efficient than the 11,000lbs nor tech stepped bottom boat, but with seeing the numbers I do think that eventually it will be worth while for me to go the diesel route.

Just out of curiousity, what do you guys with experience think a 10,000 (dry) 36' apache with a couple 480 yanmars and asd-8's do speed wise? I am guessing cruise @ 50 and top end of 74mph. Am I dreaming, or is that possible?