I read a book many years ago that gave a rough formula for the natural speed of a boat.
Simply put, this is the speed at which a boat can move through the water
with very little effective friction. A speed at which the boat, once moving, will continue to move with almost no effort(according to the author).
The formula computed a speed of something like 2 knots or so for my Venture 25.
Now I have a Newport
28 and I want to go electric
If I can figure out the "natural speed", for my boat, that will be my target speed for slow, leisurely travel when the duldrums hit.
Higher speeds will be used only as needed . . . not to make the next bridge or a supper date.
I will still have to figure wattage/amps used at higher speeds and will remain cognizant of that effect on my range.
But, for those times when I am willing to travel at my "natural speed", my range will be very substantially increased . . . maybe to the point where a solar
panel will actually supply more than needed wattage.
My comparison to what "natural speed", occurred with my Venture 25, having found myself with only a foresail and about 5 miles downwind(a light wind), from my dock
, many years ago. My battery
was an old, near-dead car battery
. When I think back, I often feel that the natural speed could be best described as a speed at which the boat will generally coast, a minute or so after power is turned off.
Anyway . . . even though at times, I could actually count the revolutions, I got back to the dock
. I actually had to turn off my nav lights after the lights drew too much power from the battery.
So, for me to go to electric propulsion
, I've decided that when the wind
dies and will no longer move me . . . that I'll be satisfied with the approximately 2 knots that will take the absoluteness of minimal power.
But now, try as I might, I cannot find the formula for "natural speed".