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props with rings ? good or bad
http://ww.w.hpbc.ca/viewtopic.php?f=19&t=3081		 Page 1 of 1
Author:  phillnjack [ September 19th, 2015, 3:06 pm ]
Post subject:  props with rings ? good or bad
is there a benefit to take off convergence rings on propellers ?
what exactly do these do and do they cause propeller drag /

I ask as I have a original omc sst 13x19 prop with a bronze ring.
the viper prop by omc/brp (from what I have read) is a SST without ring but longer hub end.

now this being a longer tube could be done on my prop as the ring is in a slight recess.
so if I take the ring off and then put on a extra piece it would then be a Viper !!!

what would be the benefit of a viper V SST with a ring.

any info on this subject please .

this is my Original omc SST with Teflon removed and a slight polish up, not bad for a prop from 1972 .
notice the bronze ring I ask about.

Image

.
Author:  beavertonae-21 [ September 19th, 2015, 6:20 pm ]
Post subject:  Re: props with rings ? good or bad
Never seen one of those before.
Author:  phillnjack [ September 19th, 2015, 6:35 pm ]
Post subject:  Re: props with rings ? good or bad
"Never seen one of those before."

WHAT, are you kidding, these are so popular on 13 splined omc's.
These were the very first stainless race props from omc available to the public in 1973.
this actual prop was used for a race from London(England) to calais (france)and back to
London in 1972 on a omc 60hp and a 13ft plywood boat.
Any old time racers in the uk would know the bloke who raced it Nobby Nievens.
it was then put back in its original cardboard box until given to me in 1999.
I never used the prop until 2 years ago, but the Teflon coating was starting to have some rust
come through so I rubbed it down and polished it up a bit by hand.
there is millions of these props around, so many have used them on engines from the omc triples
and anything with a 13 spline from omc, even seen a e-tec 90 wearing one.

But only recently I knocked off the ring deliberately to see how it was put on, its just a very tight press fit in a slight recess.
But what I want to know is what good do they do if any, and would it be better to get rid of it and just press another pice of stainless on that makes the hub longer ?

what the reason behind longer hubs ?
Author:  DoktorC [ September 19th, 2015, 7:15 pm ]
Post subject:  Re: props with rings ? good or bad
I think they are there to prevent low speed cavitation during planing and cornering. I know I lost one off my 35hp when I was a kid and the old Humber jewel didn't work so good. I don't pretend to understand OMC "engineering" but I think that was the idea. I'd leave it if you're running the gearcase buried....
Author:  phillnjack [ September 19th, 2015, 7:22 pm ]
Post subject:  Re: props with rings ? good or bad
yeah I hear what your saying doc.
But why are they now using longer exhaust hubs with same blades ?

and lots of props not having these rings, mercury had the bell ended props. some omc had bell ends too.
but now they all seem to have gone from the expensive props.
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