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Old 02-02-2006, 01:19   #1
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Folding prop. - geared vs non-geared

I have an old Eliptec two blade folding prop that came with the boat. It's starting to get pretty sloppy and I want to rebuild it. But, I see they have a geared prop now (Geartec).

I was wondering if anyone else has the geared prop and if it has any down-falls????

It looks like a better set up then the old version. One problem I have with the non-geared is if some sea grass or weed gets wrapped up in the prop., sometimes only one blade comes out and it shakes like hell until I throttle down. If I go into reverse then back into forward it usually kicks it out on the first try.

Anyone else have one????
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Old 02-02-2006, 08:51   #2
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Prop

I would get rid of any non geared prop. What if you fell in the puddle and someone else was trying to rescue you. In the excitement ( lets assume they were excited about trying to rescue you ) only one blade opened and the strut broke and or the strut pulled out of the hull. You would have a fish eye view of your boat sinking. I replaced my strut a couple of years ago, the old one snapped.
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Old 02-02-2006, 11:44   #3
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There are several negative issues with non-geared props. As we all know, the first being the inefficienccy in reverse. The second being the habit of one blade not opening properly. But the third is the response to the second. Out of balance issues get transmitted to some very criticle parts of the drive system. The first being the aft shaft bearing. The second being the shaft seal. Depending on shaft length and RPM, the distance between the prop and any other component can be at a "Critical" length. Much like how a guitar string vibrates. The "resonant" frequency of the shaft can be such that vibration can be amplified to enourmouse amounts and cause major damage to bearing and seal components. The prop is one end of that string, the engine being the other. Every component inbetween and along the shaft can be subject to seriuose stress. Of course, the last part of the shaft in this instance is the engine and how it is mounted. So even the engine mounts can get a hammering.
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Old 02-02-2006, 12:37   #4
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Reverse

My Martec non geared prop was better in reverse, than my new Slipstream geared folding prop, which is better in forward.
Depends on the design which is best. I am prepared to sacrifice some reverse for better forward. But they all work in reverse to stop the boat when needed. However if you have a current pushing from behind running at 10 knots, plan on using other braking / breaking methods.
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Old 02-02-2006, 19:19   #5
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Find! I didn't want to do any welding and machining anyway.

It looks like a Geartec is in the future.............._/)
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