Fuel consumption

[black1998]

Hello,

i'm planing to put on twin 115 HP Honda's. Doe's anybody knows how much the fuel consumption will be. Also the max speed is importand to me because i want to use it as a workboat in Croatia.

Best regards
Christian

[Brian.Dixon]

I'm sure the Yamaha web site can help more with this, but a rough estimate of fuel economy with a single outboard on this boat is about 5 gallons per hour at 20 knots, or about 4+ nautical miles per gallon at typical displacement.  Using twins is less efficient, but by how much ...I don't know without checking in with motor manufacturers and what not.  Your propeller selection and cruise speed will make a big difference.  (I always suggest a FloScan and then operating for maximum efficiency.)

Brian

[Ed Snyder]

I'm sure the Yamaha web site can help more with this, but a rough estimate of fuel economy with a single outboard on this boat is about 5 gallons per hour at 20 knots, or about 4+ nautical miles per gallon at typical displacement.  Using twins is less efficient, but by how much ...I don't know without checking in with motor manufacturers and what not.  Your propeller selection and cruise speed will make a big difference.  (I always suggest a FloScan and then operating for maximum efficiency.)

Brian

I asked one of the outboard suppliers here, he said with 2 out boards you loose 25% efficiency through prop cavitation - i.e. 2  @ 100HP you would loose 50 HP (2 X 100 = 200 - 25% = 50) that seems too much for me, we went to 1 @ 200 HP Honda 4 stroke on the 28 Ft'er Prince Rupert