Mateo, "Yes, that 20kW dc generator is powered by a 40hp diesel. Probably only needs to run a few hours per day if motoring at 6 kts."
Well let's run the numbers, 5.5 hp for 7 mph. 11 hp is apx. 8 kW. 8 kW to the engines and 12 kW to the batteries each hour (for 8 kW), seems to work if you have the batteries and the dc generator can continuously produce 20 kW.
Here are the fuel burn figures. Diesel burns .4 lbs per hp. At 30 hp the diesel is burning 12 pounds or (12/7.2) 1.7 gph at 6 knots or 7 knots per gallon (because you are only running the diesel every other hour.
If you had a little diesel directly powering both props at say 13 hp (both hulls) then it is 13 x .4 = 5.2 lbs (5.2/7.2) .72 gallons per hour and 8.3 knots per gallon.
With solar panels supplementing the electrical production, the diesel hours will be reduced and the battery time lengthened. Maybe even to where you run the diesel for half an hour and run on solar and battery for 1.5 hours. .8 gallons for two hours at 6 knots equals 15 knots per gallon. That is pretty damn good mileage for an 18 meter boat.
__._,_.___
Posted by: taladorwood@yahoo.com.au
| Reply via web post | • | Reply to sender | • | Reply to group | • | Start a new topic | • | Messages in this topic (17) |
.