Diesel 356 MPG?

[serpa4]

Good day. Can you help with some fuel consumption numbers?
Why? I do a lot of boating and lots of quick trips. I still work, so going somewhere for a month or weeks is not really possible. Thus, I like to cruise out faster..20mph and drop anchor for a 2-3 days and then head home. Range and fuel consumption is important; Bimini, Fl Keys, etc.

I'm considering holding off on a 356 purchase till I find a diesel (still working, not retired, so I can wait awhile). One just sold, missed it. I have consolidated a lot of MPG numbers on various carvers and a 356 seems the right size for my wife and I. I'd like to bop around the keys and Bahamas in it. Range is important at cruise speed (200 miles or more) and best mpg at hull speed when not in a hurry. I cannot find the numbers for a 356 diesel.
What MPG do you get at 7-8 mph? What do you get at best cruise,15-20mph or what is the sweet spot? The only diesel carver I have read about is the 38SS with Volvo IPS diesels. Incredible fuel economy for a 38' boat: 3.83mpg/7.7 mph or 2.07mpg/10mph. At cruise it shows 1.14 mpg at 28 mph for about 290 miles range. I hope a diesel 356 would be better than a diesel 38. The 356 is a few thousand lbs less. I'd do a 38, but don't want a boat that large. A few feet shorter (C356) would be nice.

[tomschauer]

I have a gas 355 (same as 356 other than rear cabin windows and counter tops), it holds about 320 gallons. I have more than 200-mile range, so I am sure a diesel would do better. I would assume the diesel would plane about the same as my gas boat, so you would either want to do 6-7 mph or 24 -26 mph, anything in between and you can watch the fuel gauges dropping.
Others can chime in here also; I love my 355. I boat on the Chesapeake Bay, normally 1-2' footers with a light breeze. When its blowing and waves are 3-4' its no fun. I'm never afraid the boat will fail, but it's a rough ride and if the waves are coming at quarter, it's a wet ride. I don't consider my boat as an ocean-going vessel.
The 38ss is a nice boat, a completely different layout than a 355-356. But overall, I think the 38 is no longer, I wouldn't rule it out for that reason.

Good luck with your search!

[buster53]

I’ve got a 356 with 8.1 Crusader gassers. I cruise comfortably in the 20-21 mph range and like Tom, I’m sure I have at least a 200 mile range. Drop down to hull speed, around 7-8 mph and you will double that. I also agree, do not run your boat between hull speed and full plane.

[Y2K996]

I have a 1993 390 CPMY (which is a 350 Aft Cabin with a cockpit added) with 215HP Cummins 6BT turbo diesels. I get 1MPG at crusing speed of 18MPH and at hull speed I am getting 2.3MPG consistently. I have 330 gallon capacity across three tanks.