Monday, June 1, 2009

Re: [Electric Boats] Re: Electric power for over 30' [Question for Dave K]



_audeojude@yahoo.com_ (mailto:audeojude@yahoo.com) wrote (below) that the
Bollard
pull of a rated 8 hp electric motor pull is nowhere near the
pull of a (healthy) 50 hp Diesel motor, which was my
knee jerk determination in the first place:
I'm not trying to start a heated debate here but just
want some kind of definitive answer.
_audeojude@yahoo.com_ (mailto:audeojude@yahoo.com) seems to have some
real-world
experience.
-Tom-





>
> Hey Dave, I am intrigued at the prospect that a rated 8 hp electric
motor
> can have the same pulling power as a 'rated' 50 hp Diesel motor!
> Now I may not understand what "Bollard Pull" is...

I'm going to comment on this as I have some real world numbers that I have
measured on outboards for bollard pulls.

300 lbs of thrust is very minimal.. it is about the equivalent of a 9 to
12 hp outboard..

I have tested 4 hp engines and they get in the neighborhood of 120 lbs of
thrust in a bollard test. 6 hp engines should get in the neighborhood of
160 lbs of thrust.

bollard tests are very much affected by size and pitch of prop also.

all the testing I did used a inline load cell rated accurate to + - 1 lb
from 1 lb to 3000 lbs. The numbers I got were reflective of industry
standards (in other words reflective of what published numbers for that horsepower
range were)

So the end result is that 300lbs of thrust is nowhere near what a 50 hp
diesel engine should have been able to produce. If you were not getting but
300lbs of thrust out of your diesel then it was in sad shape or badly
mispropped.

**************An Excellent Credit Score is 750. See Yours in Just 2 Easy
Steps!
(http://pr.atwola.com/promoclk/100126575x1222377040x1201454360/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd=Jun
eExcfooterNO62)

[Non-text portions of this message have been removed]

__._,_.___
Recent Activity
Visit Your Group
Give Back

Yahoo! for Good

Get inspired

by a good cause.

Y! Toolbar

Get it Free!

easy 1-click access

to your groups.

Yahoo! Groups

Start a group

in 3 easy steps.

Connect with others.

.

__,_._,___

No comments:

Post a Comment