In E3m0f.78$784.41@lakeread08 "Glenn Ashmore" writes:


"Lauri Tarkkonen" wrote in message
...

Any reason Autoprop is not on your list? Price?

I had a two bladed Gori, and think this is perhaps the best two bladed
folding prop. But when I wanted to change to a three bladed feathering
prop, I ended up with j-prop: http://www.bomon.com/jprop/.

I have been very happy with the performance and here in Europe it is
much cheaper than the competition.

There is one question you should pay attention to: If your gearbox has
not about the same reduction ratio of revs on both the forward and
backwards gear, then you better to get an feathering prop that can be
adjusted to different angle of attack of the blades on forward and
reverse. I know J-prop does not have this, but only a few have. It is
possible maxprop has.

AutoProp is a neat idea but I eliminated it for a couple of reasons. First
it is not truly feathering. The blades hang loose when idle and produce
some drag which can make them rotate. The other is that it relies on 3
races of exposed ball bearings that I am afraid can get caked up with
barnacle cement and other trash.

If your propeller axis is not perfectly horizontal the three bladed
feathering propeller will vause some drag. I have not heard about the
problem of Autoprop would rotate, but if you put your gear on, I am sure
it will not. I have been asking people who have Autoprops, when I have
seen them working on their boats, but even if there have been some
barnacles on the prop, nobody admitted that it has affected the rotation
of the blades. Of course most people I have met are in the Baltic, where
the barnacle problem is not that big.

I had not thought of the J-prop but I will look at them. The 3 bladed Gori
and MaxProp are near the top of my list.

If you have to fix the angle of the blades differently for forward and
reverse then MaxProp is yours, if it can be symmetric J-prop comes much
cheaper (at least here in Finland). If you choose a Gori, you should
check the vedge that locks the propeller in the axis. Earlier they were
made of brass, and I know a couple of cases, my own boat included where
the vedge has been split into two and the propeller has fallen off.
(They could not find it in the mud of the harbour bottom. :-)). Use
steel.

- Lauri Tarkkonen


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
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