Prop drag

Mar 28, 2011
261
Sebastian,
You hit the nail right on the head!!!
Nuclear power is the only real solution. Take Cin Cin she has been nuclear powered since I bought her back in '83. Nuclear powered?? Of course it's quite logical: It became quite apparent the first time I took her out for a sail. The sun's fusion creates light. Light hits the water in different spots and creates heat. Heat rises and creates wind. Wind moves the ship. Ergo - Nuclear power !

Frank Gallardo Jr
V-2184 Cin Cin

brockhaus77 kuhn@... wrote:
Hi Steve,

I hate to admit it, I AM a Physics professor, but I can't claim
particular knowledge on the drag problem. This falls clearly in
the realm of fluid dynamics (which is a rather complicated subject)
while my specialty is Nuclear Physics (now THERE is an idea for
repowering, instead of those Diesels...;-).
Well, I'll try anyway:
For a simple picture, consider that the surfaces of the prop are
tilted, so that if the prop is locked, water streaming against them will
be diverted sideways. This costs energy and will undoubtedly contribute
to drag. If the propellor were rotating exactly at the right speed, it would
"slice" through the water without diverting its flow - saving that energy.
However, it all depends on how much energy goes into friction (and how
effective this "slicing" will be) if you simply let the prop rotate "freely".
I actually have a different reason to keep it in "neutral": This will allow me to
start the engine more quickly in a sudden emergency, not having to fiddle with
my power/transmission control (single handle for both). Now of course there
is the competing concern about wear and tear - I certainly hear the
"whining" but so far have considered it an added benefit - a "poor man's
audible log". So the real issue is which parts might get impacted adversely
if one lets the prop spin freely over the long run?

- Sebastian (Vega Lyra 1060)
 
Oct 31, 2019
51
My 2 cents worth:

If you have a digital camera - use it. Take pics before you rip out the old
wiring. After your rewire use the camera to record connections at junctions
(bus bars) that are hidden or hard to see.

If you are thinking of up grading to LED's contact me off list. I am
working on a source for them.|Garry|
Albin 82MS "Half Moon"
@ Horseshoe Bay B.C. At 01:58 AM 15/11/2005, you wrote: