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Old 01-23-2017, 01:49 PM   #1
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Prop Rotation?

I read that the Gulfstar 36's from the 1970s did not come with counter-rotating props. As a result, prop-walk could be pretty severe. True or false?

Also, did the 43's from that era also come without counter-rotating props?

Thanks.
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Old 01-23-2017, 02:15 PM   #2
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I have cruised a sailing catamaran with twins with co rotating props and could never really notice any prop walk. Twin engines, whether co or counter rotating make it easy to back up the way you want to go.

And FWIW there are two ways to get counter rotation: one engine turns backwards (Perkins and DDs) or the transmission reverses the prop shaft output.

David
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Old 04-29-2019, 01:58 PM   #3
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Prop rotation

Our 74 43 has a right hand turning Perkins.
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Old 04-30-2019, 07:11 PM   #4
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My 36 MrkII has both left hand, and I have no issues backing down.
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Old 04-30-2019, 08:55 PM   #5
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Borg Warner gears of that vintage did not have the same ratios when rotation was reversed by one. 1.91:1 and 2.10:1. Close, but not the same. One prop had to be about one inch off in pitch, and different prop rpm set up some unpleasant harmonics. I could see the rationale to spin the props the same way.
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