Fuel Consumption Question

[Hold Fast]

Good afternoon

I have a 1973 36'C that I purchased last July. She has a pair of the Cummins 6BTA-5.9M2 at 300hp. I have a set of flow meters for her but have not installed them yet (have been working through a good to-do list, but the flow meters are at the bottom).

My question is, is there anyone in the forum that has one of the older 36'Cs with the 300hp Cummins and a set of flow meters? If so, can you tell me what kind of fuel consumption you are getting at cruise? (My engines top out at 2800 rpms and I cruise at 2400 rpms).

Any info would be greatly appreciated.

Thanks

Billy Groves
HOLD FAST

[34Hatt]

Well I have a 34C with the Cummins 330 which are 315 hp I cruise 2400 to 2450 burn 20 gallons. I don't have flow scans but have tracked it so much I go offshore fishing and use 20 X time @ cruise and 3.5 X at troll calculate it up and come within a gallon or so at fill up.
Your should be very close to that!
Hope it helps Dan

[drburke]

Dan, thanks for those numbers!

DAN

[Hold Fast]

Dan

Thanks for the info.

Billy
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[REBrueckner]

If that post suggests about 1 NMPG at cruise, around 20 or 25 knots or so, that would seem about right.

Big modern sportfish, say 60 to 80 feet, with modern four cycle engines might get 1/2to 3/4 NMPG in the 20 to 25 knot range, perhaps 10% or 20% less at 30 or 35 knot cruise. I'm guessing those are typically lighter than vintage Hatt Sportfish and the combination of lighter and more modern hull designs, computer scanned props and four cycle computer controlled engines gives them considerably greater efficiency.

[Mike36c]

My 1977 36c with 330 (315hp) Cummins and Flowscans gets slightly less than 1nmpg at cruise. She's a little heavy with a 9kw genny, ice machine, extra freezer, stone counters, etc. The interesting thing is once on plane the mpg doesn't vary much between slow, mid and high cruise. I cruise around 2450rpms just to give the engines an easy life. Oh, make sure you turn 2900+rpm's full load if plan on keeping your boat, these engine do NOT like to be lugged.