How To Install a New Diesel

[gert]

by Peter Cumberlidge:

http://farm3.static.flickr.com/2451/4034863466_90177960e5_o.jpg

I can't get his formula to work for his own boat never mind my total displacement of 4500 lbs & 6 knot hull speed.

But then I did flunk math 10 twice :eek:

Any one able to help here; this is to figure out "optimum" motor size for GS.

[James McMullen]

I've got the Grey Seal plans myself, and the way I look at it, the very smallest diesel you can find that will fit in your space--and it will just barely fit--has more than enough horsepower for your needs. I'm pretty sure that any 7-10 hp diesel would work, and they don't come any smaller than that, I think.

[Todd D]

Here is the reagganged formula solved for horsepower.

HP = D/(((10.665 x SQRT(LWL))/S)^3)

D = displacement in lbs
SQRT(LWL) = square root of waterline length (ft)
S = speed in knots
^3 = raised to the third power (i.e., cube)

Just algebra

[willmarsh3]

There's an issue of WB #128,#129, #130 that has a 3 part article on the build of Grey Seal. They used a Vire 7 gas engine which is presumably 7 hp.

[norseman]

4 hp pr ton,Bruce Roberts.As James said.

[David W Pratt]

Truth weighs 11,000lb, has about a 27' waterline and will hit hull speed with a 12 horse diesel turning a two bladed prop through a 2:1 reduction.
Good Luck.

[gert]

An associate at work figgured it out; the 10.665 is a "constant".

GS (loaded) will need 6.1 HP, at the shaft.

Doesn't sound like the Bukh DV-7 ME will quite cut it.

[andrewe]

The standard choice seems to be a Yanmar 1GM10. Mostly on cost/size basis. Know to be a bit lumpy on tickover though.
A