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paladin
05-12-2007, 04:58 PM
Just punching numbers on the tug project......at 25 feet it displaces 15,146 pounds......CB is 53%aft of station 0.......17 hp and a 21 inch prop pushes it to 7 knots while using less than 1 liter per hour of fuel....:D :D anyone wanna try for a powered circumnavigation on the cheeeeep.....
Paul Fitzgerald
05-12-2007, 06:19 PM
How did you calculate the fuel consumption?
I work on 0.2 liters per Hp per hour for diesel.
Do you mean one gallon per hour?
JimD
05-12-2007, 07:17 PM
...anyone wanna try for a powered circumnavigation on the cheeeeep.....

As a matter of fact, yes. How much fuel would you need to carry for the longest leg?:cool:
paladin
05-14-2007, 03:41 PM
No Paul....wrong chart in my notebook.....I was going back over the chart figures for loaded hp at the wheel and was working with one engine and looking at another fuel consumption chart.....But...it still isn't bad...I was using the 28 hp Beta marine diesel with the 2.91:1 reduction figures and a 21 inch prop......the "true" consumption at rpms rated at 18 hp is 1.8 liters per hour.....and by going to a 37.5 hp Beta, same reduction, but the engine reaches max power at lower rpm I can achieve the same figures at the same rated hp....this is of course not counting the hp/fuel needed with the alternator working or any hydraulic accessories......however, the displacement of the craft will allow more fuel to be carried. The idea is to cruise as far as you wish throughout the year and only refuelling at the least expensive spot when and where you can....perhaps once a year when cruising........with an engine rated at 12-14K hours between overhauls....or more......
Matt J.
05-14-2007, 04:30 PM
Just punching numbers on the tug project......at 25 feet it displaces 15,146 pounds......CB is 53%aft of station 0.......17 hp and a 21 inch prop pushes it to 7 knots while using less than 1 liter per hour of fuel....:D :D anyone wanna try for a powered circumnavigation on the cheeeeep.....

Sounds pretty close. Rarus has 10HP, is 20LWL, displaces somewhere around 10kip, and burns around IIRC 1/3gph. Max speed seems to be around 6 knots.