Cruising Sailors Forum Archive
I find the Wyman relationship between the most accurate for estimating power required under moderate conditions...
In Response To: Todd, what calulator are you using? Is it online? 
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() Wyman: SHP=(Disp/1000)*(KTS/(LWL^(1/2)))^3
SHP = shaft horsepower
Disp = displacement in pounds
KTS = speed in knots
LWL = waterline length in feet
The Keith formula works well for calm conditions (flat water, no wind)
Keith: SHP = Disp*((KTS/(11.963*(LWL^(1/2))))^3)
These formulae are discussed in the link I posted above.
Messages In This Thread
- How many NMPG does your boat get?
- Around 12
- Were you doing a lot of battery charging or slow speed?
- I just had a mechanic down to the boat discussing
- I'd give him the 8 hrs plus 15%
- I would pay for the time to do the required repair...
- I have used this fellow in the past and have
- I'd give him the 8 hrs plus 15%
- Around .33 gallon per hour or
- Really apples and oranges?
- My a5 year average fuel consumption is 0.45 gph
- Right around 7 NMPG
- 4+ 130 hp 6-354 Perkins pushing 42,000 lb
- I seem to burn about 1.05 gal/hr...
- Volvo folding prop -- 16x19 three blade
- meant 19x16
- Well, I don't agree with the "always run it at 80% +" crowd...
- Given your fuel consumption you are likely putting out 17-18 hp...
- Todd, what calulator are you using? Is it online?
- I find the Wyman relationship between the most accurate for estimating power required under moderate conditions...
- Todd, what calulator are you using? Is it online?
- Given your fuel consumption you are likely putting out 17-18 hp...
- meant 19x16
- Volvo folding prop -- 16x19 three blade
- With my 80 gallon diesel tank, I'll probably never really know.
- Around 12
