38C Series II, 6-71/485 Covington's

[Freeebird]

Just wondering if anybody has run one of these with this power option. One recently sold in TN, and the new owner is taking it from Nashville to Mobile via the Tenn-Tom. Just curious as to what kind of fuel numbers he could expect on plane. I'm guessing it would be pretty thirsty but have zero experience with that power.

[Jim saco]

I would say 35 GPH. That’s a combined total.

[Freeebird]

Based on a magazine article linked to the brochures section here, the 455HP version turned 29MPH @ 2,100. I did find a Hatt owner (on another forum) who claimed 27GPH @ 2,100 with these same 485's, so that's better than what I (or the new owner) would have expected. Not sure what size Hatt, but for this purpose, it doesn't make much difference. Was just hoping to find someone who has hands on experience with this particular combination, but it looks like he should expect right around 1MPG vs the .5 max he was guesstimating.

[Jim saco]

I have 6v92’s rated at 550 hp in my 41c. If I’m loaded with fuel and water and all the the other essentials. I burn close to 40 gph at 1950-2100.

[Freeebird]

I have 6v92’s rated at 550 hp in my 41c. If I’m loaded with fuel and water and all the the other essentials. I burn close to 40 gph at 1950-2100.

At what speed?

That's one thing that has always puzzled me is how meaningless (not directing this at your comment) GPH numbers are vs MPG numbers. I'm certainly no guru on these things, but you're running 552 cubic inches vs 426 in a smaller, lighter boat.

Bottom line is, I'm sure his estimate of no more than .5MPG on plane is inaccurate... in a good way.

[MikeMck]

I run a 37C with 671N's cruise on plane 15 to 16 kts. Burns 25 GPH or .7 Miles per Gallon. I would be surprised if he got 1MPG at cruise.

I could be wrong.

I did get her up to 23MPH once. Of course that was on the Mississippi compliments of a 7 knot current.

[Freeebird]

I wouldn't expect 1MPG at 2,100 either, but that's what it works out to if the other guy's GPH numbers with these same engines are correct. That was an old post on another forum (via a Google search), so I couldn't ask questions. Still hoping to get input from someone who owns a 38C with this same power.

[cenger]

35GPH is about right if you run them at 21RMP. I had a 40' Viking with those engines and that is about the burn rate. At 21RMP was running at 18-19knots.

[jim rosenthal]

Just curious, Bird, do you know if this boat has EGT and pyrometer gauges? I have no idea what mpg she will get, but that would be the way to run it most efficiently, seems to me- minimum EGT and moderate boost.

[captcrunch]

I have the same boat with the j and t 485hp engines. 35gph at 2100