GL: Hyper Miling

[Luther]

Well said Mr Barnes,


I find that cruising at 6.5 to 8 knots is very comfortable and to estimate fuel consumption I have always referred to gph. Travelling at the speed of say 6 knots and be hit with a 2 knot counter-current, I have just taken a 33% impact in mpg. However when estimates are based on the gph I have a warmer feeling for fuel requirements.

Luther


--- On Thu, 6/26/08, Tom Barnes <tomb215 at yahoo.com> wrote:

> From: Tom Barnes <tomb215 at yahoo.com>
> Subject: Re: GL: Hyper Miling
> To: great-loop at lists.samurai.com, valhalla360 at yahoo.com
> Date: Thursday, June 26, 2008, 8:28 AM
> 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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