This same topic came up on the C30 list and some retired rocket engineer showed through equations, parens, to the umpteenth power that rotating prop does not cause any more resitstence then fixed. The best fix for the Hurth tranny was to keep in reverse while sailing to prevent undue wear. Clyde Thorington ex C27 now C30 San Jose, CA
--- On Wed, 9/9/09, Judith Blumhorst, DC <[email protected]> wrote: From: Judith Blumhorst, DC <[email protected]> Subject: Re: [IC27A] Re: new noise To: [email protected] Date: Wednesday, September 9, 2009, 11:28 AM I googled it the issue once and didn't come up with any real experimental data... just a lot of opinions.... so, my carefully considered answer is: I have no answer. :^) Curious minds want to know..... Fair winds, Judy B ____________ _________ _________ __ From: "jenngsj...@aol. com" <jenngsj...@aol. com> To: ic...@yahoogroups. com Sent: Tuesday, September 8, 2009 3:01:31 PM Subject: Re: [IC27A] Re: new noise Interesting comment on freewheeling prop adding more resistance than one that is locked. Would like to hear more comments from our C27 "experts". What say you Dr. Judy? John Jennings 83 C27, 5267 Inboard with FREEWHEELING PROP In a message dated 9/8/2009 5:49:14 P.M. Eastern Daylight Time, leroy.sailorman@ yahoo.com writes: --- In _ic...@yahoogroups. IC2_ (mailto:IC27A@ yahoogroups. com) , "dsavlin" <dsav...@... > wrote: > > I do the same. Lock tranny in reverse. I saw a post that suggested a freewheeling prop adds more resistance compared to one thats' locked under sail. Counterintuitive ? //leroy > Dunno how significant this is, but in my Universal M-15 manual, it > states in all caps, underlined, and bold letters, never to put the > transmission in forward gear while under sail; always use reverse gear, > if you do not want the shaft to spin free. > > On Persephone, we do this to reduce wear and tear on the cutlass bearing > and the packing gland. It probably costs us a small amount of speed but > we're pure pleasure cruisers so we don't care. Our cutlass and packing > gland are both still in fine shape after 7 years of ownership. > > David > Persephone, '88 C27 > > > --- In _ic...@yahoogroups. IC2_ (mailto:IC27A@ yahoogroups. com) , "new_horizons_ , <new_horizons_ new> > wrote: > > > > If it is not your prop shaft spinning free, it is most likely your > cutlass bearing rattling within its strut, which indicates that it's > failing and needs to be replaced. I had the same noise when mine was > failing. It sounded very much like the prop was free-spinning under > sail. > > > > --- In _ic...@yahoogroups. IC2_ (mailto:IC27A@ yahoogroups. com) , "sharon_speller" unclesharon@ wrote: > > > > > > I had a new mystery noise coming from the stern cowling that is > connected to my blower hose. The noise happens when i am under sail, > engine off. All batteries are off. If im at the dock nothing. it sounds > like a motor whirling. the noise is coming from behind the engine. Near > the transmission and prop..... I think. > > > Could it be the prop? never had it happen before today. > > > thanks. > > > > > > [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] [Non-text portions of this message have been removed]
