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Subject: Re: Leg 56 Question # 3
From: Robert Owens (tugly@XXX.XXX)
Date: Tue Jul 20 1999 - 09:02:01 EDT
-----Original Message-----
From: Lu Abel <lu.abel@XXX.XXX>
To: NAVIGATION-L@XXX.XXX
<NAVIGATION-L@XXX.XXX>
Date: Monday, July 19, 1999 10:46 PM
Subject: Re: Leg 56 Question # 3
Snip-----
>Way behind - The USPS courses, for example, discuss obtaining speed vs RPM
>curves for one's boat. Good 1920's practice when electronic knotmeters
>didn't exist. Maybe actually carried into the 1950s by the Navy. Has
>anyone on the list actually made such a curve?
>
Snip
I did a Speed vs RPM run after I bought my boat.(26' Nordic Tug) It took me
practically all day but I now know how fast my boat moves through the water.
Then I calibrated my knotmeters. Both were off quite a bit to my standards
and both have adjustments and come with instructions on how to do it. I have
both Loran and GPS and do not trust either as true speed indicators.
Although the loran is much more accurate than the GPS. I have seen errors up
to 1.8 knots on the GPS. Try doing a predicted log event with nothing but a
tach and compass. Using your arguments about the 1920's why bother
compensating and adjusting your compass.
I don't see the difference between a boat and an airplane as far as how fast
does it cruise at certain RPM's and how much fuel do I burn.
I go at this at a ridiculous extreme. Two decimal points. But I win my local
predicted log events and can tell you how much fuel it will take to fill the
tanks to the quarter gallon. If I run out of fuel it will be a leak. This
dribble is just my opinion.
Bob Owens
TUGLY
26' Nordic Tug
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