Traditional Steam Launch Propeller

[Lopez Mike]

In my area the problem is Eel Grass and it gets wound up in a ball so tight that a plastic fork would likely break. I like Bart's war weapon but I'm afraid it might frighten visitors! A weapon of, if not mass destruction, at least medium destruction.

It's such a sneaky problem. The revs don't drop, just the speed. Sometimes there is a slow buildup of vibration.

Mike

[PeteThePen1]

Hi Folks

Thanks for the suggestions and I particularly liked the linoleum knife. I was not expecting UK Google to even recognize such an archaic word, but it did and the ones available here are not that much different in price. Bart's fiendish weapon remains a mystery as Homedepot.com appears to be a prohibited site this side of the Pond.

Whilst the hypothesis that the traditional propeller is good for weed may well be wrong, I have struggled on with attempting to draw the thing. Attached is my first completed attempt which is in the right direction but well short of the goal. Way too many false starts and cul de sacs are hidden in the code. However, I think I now have a clearer idea of how to draw it for V2. If any kind person happens to have a photo looking down a blade I would appreciate a copy as that would help me confirm my calculated angles for the blade at different points.

Propeller (474 x 376).jpg.jpg (8.74 KiB) Viewed 1197 times

Regards

Pete

[RNoe]

Pete:
These photos are not directly side on, but might help.
The prop is on a layout board I made to finish the propellor, and the circle lines are 1" apart. (2.54 cm for most of the world.)
RussN

[fredrosse]

Just convert to a paddle wheel steamer. Margaret S. easily operates in weed infested areas with never a problem.
https://www.youtube.com/watch?v=9krkmNjS6nk

[Lopez Mike]

Fred, I love your boat. Especially the measured cadence of the exhaust. Much more dignified than the busy whirring of our screw driven craft.

BUT. I suspect that a decent case could be made that a propeller, even burdened by a fairly significant load of weed, is more efficient than a paddle wheel, even an articulated one.

It is a fact of physics and hydrodynamics that flow across a foil (read: propeller blade) is far more efficient than stalled flow (read: paddle).

Point taken, though, about the self cleaning aspect of a paddle wheel. I were to build a craft intended for shallow and weedy waters I would look very favorably at either a side wheel or stern wheel.

Mike

[barts]

Yeow! What a toad sticker. I guess one would be prepared for pirates as well as weeds.

Mike

When my Leatherman's serrated blade took minutes to saw through that crab pot buoy line, I decided I want something fierce. I was nice and knotted the cut line ends together once I'd managed to free them from the prop.

I really like these traditional looking propellers; I wonder how they'd deal w/ a debris strike, though. Up here in the islands we get a lot of wood in the water...

- Bart