Re: Screw size and speed

[VBra676539@aol.com]

In a message dated 7/19/99 5:19:17 PM, jonnie@chronic.lpl.arizona.edu writes:

<<	In RE: Superiority of big geared-down screws, any thoughts or
experience on fouling? Problem with being a "bottom dweller" is that there
are -things- you can wind up amuck in, like cables and so on. I worked
around ducted small screws to keep a clean smooth profile, but realize the
performance penalty. Hearing more about the Perry subs has really piqued my
interest, though.
	Did any of the Perry boats ever have trouble with those big screws 
and entanglement when they weren't under power?


							John>>

weren't under power? Biggest problem was keeping stuff out when they WERE 
under power. I think I'd put line cutters on one if I were duplicating it 
today. In fact, I'm designing a reduction gear pkg for my K-boat that will 
let me turn an 18" prop, so will have to keep in in mind to make sure the 
space on the shaft is allowed for.

And let me tell you, it is mighty comforting to be able to kick the sub a 
hard one in the butt and have it MOVE, and I mean right now. Smaller props do 
the job, but it's going to take a minute. Which is fine if you've GOT a 
minute.

Vance