venturi

[romantic comedy]

Bill are you familiar with Snow Lilly? It is a Tartan 34 that was restored beautifully.

He changed to electric power and extended the keel for a larger prop. No strut was needed. I dont know T 30s, but check it out.

I would like to be able to do something similar, with the prop, not the power.

http://www.lackeysailing.com/archived/snowlily/snowlily.htm

[BadaBing]

Ill check it lut thanks. I keep an eye on the state-of-the-art in the electric propulsion upgrades every now and then. I'm fascinated by the idea however the cost of lithium ion batteries and a means of recharging for extended cruising remains a problem especially for a model hull.

If I were simply day sailing and something were to happen to my Atomic 4, please pardon the sacrilege, I would go to Electric.

[hanleyclifford]

I don't understand the discussion over prop size. If you are running a 12x6 now, there is plenty of room for a 12x12 once you go to reduction drive. And BTW, the idea of electric drive is not as far out as some may think; consider how diesel-electric train engines operate. It is not too far fetched to think of the A4 as a generator:

[BadaBing]

unfortinitly a 12" prop will not quite fit unter a t30 hull. Not posative at the moment but I think9" was opimum max.

[romantic comedy]

For my Tartan 34 I am running the Indigo prop. It has performed pretty good. I can only compare it to the 12X6 two blade that I had.

The blade area of the Indigo is less then that of a 12X12 three blade. SO I wonder about the drag under sail, comparing the two.

A 12 inch wheel only clears by about an inch, so that is closer then I would like. I like the idea of extending the shaft back so I could get 2 inches.

I know that diesel electric is very popular with ships, and trains. Many modern ships dont even have tradition shaft thru hull propulsion, from the TV shows I see. I am not an authority.

I am fascinated by electric propulsion. With solar being more efficient and cheaper, it may be a viable alternative. I dont keep up with how things are going. I just see it more lately. I am a motor head and am used to fooling with mechanical things. but a silent motor would be incredible.

[hanleyclifford]

I can only conclude that a boat so designed that it cannot carry enough propeller to drive it thru conditions likely to be met by the operator offers a splendid re-engineering challenge and opportunity for it's owner.

[Ball Racing]

On the exhaust thing.
I still only have 1 1/4" exhaust and now am turning 3,600 rpm.
No signs of restriction.
Many a V8 car came with single 2 inch exhaust in the 60's-70's-80's
Making at least 200hp
But my exhaust has no muffler and is only about 6 foot hose length....

[BadaBing]

Daniel

would you mimd recounting the magic you used to squeeze all those rpms out of your engine, plaese?
I think I recall that your usimg a plaining hull? which in itself has some.voice in the matter but your successs can teach us all a great deal.. Thanls
Bill

[Ball Racing]

Yes, I have a 19ft. wooden v bottom planning hull.
One head gasket, multi angle valve seats, deburred ports mobil one motorcycle oil .
I also run my valve guides as tight as possible for better seal.
I run tight ring end gaps
10.5x6 prop 3 blade
Reducing underwater drag has helped me a lot..