Detroit 671 Fuel Burn on 45' Ocean?

If they are putting 485 HP, then the fuel burn is 25 gph per engine

good luck with the boat

2100 rpm on the TIBs should be pretty close to 14 gph each side
At WOT you should be at 25gph per side

I curse my TIBs 2000-2100 RPM depending on sea condition, load and desired speed.
At 2000-2100 RPM I burn between 12 and 14 gph per side

The key factor is that you must be able to get 2550 at WOT under full load.
Otherwise you will overload the engines.
An overloaded TIB will have a short life.

A really good tool is the pyrometer. IF you don't have them, consider having them installed.
I think EGT of 750 with a max of 800 is where you want to cruise the engines.


when properly loaded, detroits will burn the same fuel regardless of the boat.

good luck

I may be wrong, but I think those speeds seem pretty optimistic for that HP and size boat. I would think knocking a few knots off may be more realistic of what you will see. Especially if you fill the boat up with stuff.

I don't have any personal experience with Oceans.

Oceans are know to be considerably lighter, flatter and narrower in the stern than similar sized SFs.
The results are that the run faster than a similar length SF.

I have a 46 Post with the same power, the boat weight 48,000 pounds.
My 46 Post has seen 27 kts WOT with the wind, current, planets aligned, and me flapping my arms on the bridge.
Realistically, I think the top speed that I could expect in most conditions is closer to 24-25 kts at 2500-2550 RPM.
My cruise speed varies from 18-21 kts from 1950-2150 RPM

wow those are some numbers!

plausible, considering 37,000 pounds in a 45' boat.

I am basing it on my 46 Post with the same power weighing 48,000 pounds and a little more beam, more draft, and 650 fuel.

Most Oceans of that era all hit 30 knots, that pretty much was their benchmark and for a decade they held the fastest production SF line up across the board of sizes they made.