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Old 09-25-2018, 07:40 AM   #67
smitty477
Guru
 
City: Northport
Join Date: Aug 2015
Posts: 2,046
Quote:
Originally Posted by mcarthur View Post
Sorry smitty...
The numbers are from the boat itself (two motors, 2400rpm, 13kn, around 3L/nm counting both motors). I only went to the engine data and curves to check against the 103gph - I much prefer 10.3gph (phew!).

You had asked "How do we explain two 135 hp diesels of that vintage consuming 10.3 gph at WOT?" and I was explaining it by a) that's what the boat gets (actual), and b) that's what the engine manufacturer quoted (theoretical). So I'm not seeing the problem...
You have an actual measured fuel consumption of 10.3 gph at WOT for both (2) 135 hp earlier Perkin diesels.

That would be 270 hp total being produced by 10.3 gph which is almost 60% less than the hp which you could/should expect from those engines burning 10.3 gph.
I believe it would be important to figure out why your fuel burn (and therefore HP) differs from the expected amounts.
These numbers are being utilized by you to guesstimate the relative speeds of increased hp in the boat so the benchmarks are very important.
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