Re: Screw size and speed

[Michael B Holt <michaelbholt@juno.com>]

On Fri, 16 Jul 1999 20:24:20 EDT VBra676539@aol.com writes:
>For what it's worth, I've used both styles, and however good the new, 
>rare-earth motors in the 1 to 2 hp range, I still prefer the big wheel. 

Thanks, Vance, for this note.   

"From My Old Boat Shop," by Weston Farmer, espouses low-RPM, 
high-torque power plants.   I presumed that concept might work for 
submerged boats, too.   

>The  smaller boats 
>turned smaller wheels, but not by much. Both PC-14s, for instance, 
>used plain  old 36 volt golf cart motors. 5000 rpm if memory serves 
>with 17 to 1 gear reduction. They turned a 28 X 24 bronze wheel and 
>ran nearly 5 knots on the surface. 

Where did Perry get the reduction gears?   Any idea if a significant
amount of energy was lost in the gears?


All this, and it seems to me that a boat with two madly spinning tiny
screws would just look and sound funny.   Big screws may inspire
more respect.


Mike Holt
-- 

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