GL: Hyper Miling

[Tom Barnes]

You know, until all the "Baby Boomers" started flooding the cruising 
scene, fuel consumption was always figured by the number of gallons 
used over a period of time at a given RPM. No one ever tried to figure
how many miles you got to a gallon. It's not like driving your car down 
the road. To many other rhings can effect it.

Tom B.

--- On Thu, 6/26/08, M S <valhalla360 at yahoo.com> wrote:

From: M S <valhalla360 at yahoo.com>
Subject: GL: Hyper Miling
To: great-loop at lists.samurai.com
Date: Thursday, June 26, 2008, 7:34 AM

You guys with your big high powered speed boats. 9 knots!!
 
Nice graph. The lines don't neccessarily cross at the same point, so there
isn't neccessarily anything wrong. A smaller slower boat will have the
lines
cross at lower counter current speeds. It will also have a more dramatic
improvement with a following current. 
 
It does demonstrates the value of slower speed with no current or a following
current. With a 3 knot following current, you get almost 4 times the milage
going 6 knots as opposed to 9.
 
With a counter current, it gets more complicated. I assume 9 knots is full
thortle and normal cruise speeds would be in the 6-7 knot range. If we are
hyper miling at say 4 knots (assuming 8 mpg), I eyeballed where the lines
would cross and at a little over 2 knots of current, 6 knots thru the water
becomes more efficent. 
 
Another point, on the graph, when you get to a 5 knot counter current, the
fuel eficency isn't much different from 6 to 9 knots. The actual speed over
ground is ranging from 1 to 4 knots. If it is 4PM and I am 10 mile from home,
at six knots I get in around 2AM. Crank up the throttle for little or no
difference in fuel efficency, I get in around 6:30pm.
 
Of course, if I could afford a nice new 48' Krogen, I probably wouldn't
care
about an extra $10,000 a year in fuel.
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