props for sailboats

[KenD]

with everyone talking about galvanic action is there a way to make a prop and shalf out of carbon fiber or a plastic compound that would not conduct electrical current, I am not an engineer of any type but wonder if we are all missing the boat so to speak by using metal castings for thru hulls and the strainers that attach to the hull, along with props and the components to get power to the transmission. would someone care to explain why these ideas can or cannot be used.With my probable poor reasoning it would seem to make sense to eliminate all exposed metal on the hull from waterline down. Looking forward to replies.

[Sailmc]

There are plastic props made now, Cruising Design among them but all you need to do is put zincs on your shaft. These are sacrificial and will take the brunt of the electrolysis. This is an ifinitely easier route.

[hamiam]

I have a device called "drive saver" whose secondary purpose is to electrically isolate the engine from the prop and the shaft.

[KenD]

Zinc and drive savers are good but if we had no metal to conduct electrolysis to the boat then we would not need the zincs,is this not true or am I missing a key,

[hamiam]

You are correct. You only have zincs so that they sacrifice themselves and the galvanic action doesnt eat away at your metal shaft and prop. Composite shafts are an interesting idea. I wonder why you never see them? Would certainly be beneficial especially to those who rarely take their boats out of the water.

[maestro]

just a thought....

why do we not see sailboats with jet drives like a jetski??

No corrosion, no prop drag,no bent shaft, no fouling the prop with anchor rode/lobster pots/various lines, etc. ???

[KenD]

I can see the wake now with a rooster tail and chuncks of what we run over! got to be better than a sail drive hanging out there,The idea behind this thread is to minimalize the metal hanging on the hull to eliminate electrolysis. If you could make a pump from plastics or other non corrosive material it might work what the heck why not plumb in a couple of gates that would open when you want to turn instead of a rudder like a bow thuster.The gauntlet has been thrown down all you marine engineers. how about telling us why the thing wouldn''t work try to use small words for people like me.

[Sailmc]

The whole concept adds much needless expense and engineering chalenge when a simple and cheap solution (zinc) is already at hand. This would truly be reinventing the wheel. If in fact this is doable which I believe it is you would be replacing a $10 fix (zinc) with a $3000+ solution.

[KenD]

I would have to agree with you on reinventing the wheel.Just read an article on sail drives. The way it was explained there is a bunch of maintainance involved and considerable cost in changing the zinc Just thought that by subsituting non corrosive materials for things like props,shalf and intake screens on boats we can possibly eliminate the need for zinc anodes as much as possible.

[hamiam]

In response to sailmc; you are partially correct but consider that many boats, including the very pricey talarias, have gone to a jetdrive system. I assume the jet drive provides additional benefits that I am not fully aware of.