GL: FW: Hyper Mileing

[Mike Malpass]

I was intrigued by the 'monkey wrench' so decided to plot it up. I'll make
no guarantees that it wasn't done too fast and that there are not mistakes,
but right now don't see any problems.  Fuel usage is per Krogen website for
48' North Sea. I am sure these numbers would/could  vary for many reasons. 

 

So here are the plots:

 

X-Axis is "Assisting Current". Positive is current on the stern in exactly
the direction of travel. Negative is on the bow. Things get interesting
between -8 knots and -3 knots (current opposing travel).

 

http://tinyurl.com/43lexz

 

Second Plot: Zoom in on -8 to -3 knot region

 

http://tinyurl.com/3n3kud

 

Yes, it does appear that fuel mileage is better at 9 knots vs. 8 knots in a
7 knot opposing current (0.340 nmpg vs. 0.272 nmpg). 

 

Another seeming anomaly. Why doesn't the 6 knot curve intersect with the
other three at the -6 knot opposing current? I initially thought hull speed
influences, but that should be close to 9 knots.

 

Give the wrench a turn. Best regards, Mike