GL: Hyper Mileing

[M S]

I'll throw a monkey wrench into the discussion:
   
  If you are in an area with no current or a current going with you, slowing down will improve fuel effiecency. If you are fighting a strong current (which is not always possible to avoid), faster may be more efficent. Example:
   
  Two Throtle settings with no current: 
  2000rpm: 5 mph 1 gal per hour = 5 mpg
  3000rpm: 8 mph 2 gal per hour = 4 mpg
   
  3 mph current against you:
  2000rpm: 2 mph 1 gal/hr = 2 mpg
  3000rpm: 5 mph 2 gal/hr = 2.5mpg
   
  Ideally you would develop a graph showing the relationship between speed, RPM and Fuel Consumption. By checking the difference between the GPS speed and speed thru the water, you could determine the most efficent cruise speed. Realistically, I use guesstimates. Trying to develop the graph mentioned would take a lot of time and effort and then as soon as a couple of barnicles sneak on board, the fuel level changes or wave action changes, the graph losses accuracy. 
   
  The other question is at what speed does it just start getting silly? Recently, I've had situations where I am at around 80% throttle and make 3.5 mph gps. If I ease up, I'm only going to make 1-2 mph. 
   
  I generally set my throttle and then if the speed drops below 4 mph gps I start throttling up to maintain at least 4 mph gps. If the current is going with me, once I get up to around 7.5 mph, I'll start backing off on the throttle rather than going faster (Recently coming down the Savanah River I was doing 7 mph with just enough throttle to maintain steerage. I'm guessing a little bit, but estimate I was getting around 30 mpg.). This maximizes fuel effiecency, while ensuring we are actually making some headway.
   
  Mike & Tammy
  Valhalla II