Joe, I was only talking about the load on the sheave, not the tension on the line. The tension on the line is more or less constant, but the load on the sheave increases with the wrap angle, maximizing at twice the tension for a 180 degree turn (like an internal halyard).
Keith Sneddon ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Joe McCary Sent: Monday, March 22, 2010 5:55 PM To: [email protected] Subject: RE: [IC27A] Re: Way Too Much Tension on the Halyards Under Load - Please Advise I don't doubt the tension is significantly higher with internal halyards but the math seems flawed. My external halyard (main) does a 180° (up the mast and back to sail's head). Mine is also run to the cockpit so I need to add 90°. I don't see internal halyards being much more than that except adding a few degrees when the line exits the mast. Joe McCary Aeolus II. #4795, West River, MD www.aeoluswestriver.net joe at photoresponse dot com From: [email protected] [mailto:[email protected]] On Behalf Of Sneddon, Keith - ES/IS Sent: Monday, March 22, 2010 2:04 PM To: '[email protected]' Subject: RE: [IC27A] Re: Way Too Much Tension on the Halyards Under Load - Please Advise The really nice ball bearing ones are just under $40 each from Catalina Direct. Also, if the halyards are internal, the loads on the sheave are about 40% higher than if the Halyards are external, because the line turns 180 degrees (vs. 90 degrees for external halyards). So, if you have the original plasticky sheaves, they are a good place to look for dragging halyards.. Keith Sneddon ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Mark Robertson Sent: Monday, March 22, 2010 1:41 PM To: [email protected] Subject: [IC27A] Re: Way Too Much Tension on the Halyards Under Load - Please Advise Does anyone know what new sheaves cost? I have my mast down and am going to rewire it and put new lights on. So I might as well put new sheaves on while I am at it. >>> "Michael" <[email protected]> 3/22/2010 11:26 AM >>> Thanks for the responses: The halyards aren't showing any excess wear (that I can see). Is there any way to check if they are binding to electrical cables or themselves without unstepping the mast? Is there a way to tell if the hole in the sheave is elongated without taking it apart; ie would it wobble a little when I spin it? I have no idea when or if the sheaves have ever been changed. There are two spare sheaves (one on either side of the ones currently in use) to which I could switch. Thanks again for the help. Michael --- In [email protected]<mailto:IC27A%40yahoogroups.com>, John Harker <jhar...@...> wrote: > > Could be the sheaves inner hole has elongated. So it spins with no load > and locks with load. How old are they and do you know if they have ever > been changed - from my experince and others on this board it is clear > the original have a finite lifespan. > > John Harker C27 Prana 6261 Santa Cruz > > Don Brooks wrote: > > > > > > Michael, > > If you are having difficulty hoisting a person up the mast with a > > cabin top winch, that's normal. You should be able to hoist the > > mainsail all the way up by hand with moderate effort. The boom should > > be perpendicular to the mast, or slightly higher to keep the leach > > loose. If that is not the case, then you should look for a > > problem. Is your halyard showing any unusual signs of wear? That > > could indicate a binding block at the base of the mast or cabin top. > > Your halyards could be twisted together inside of the mast or binding > > on the electrical wiring at the mast base. > > Don, #6293, Niceville, FL > > > > --- On *Sun, 3/21/10, Michael /<mlong9...@...>/* wrote: > > > > > > From: Michael <mlong9...@...> > > Subject: [IC27A] Way Too Much Tension on the Halyards Under Load - > > Please Advise > > To: [email protected]<mailto:IC27A%40yahoogroups.com> > > Date: Sunday, March 21, 2010, 10:22 AM > > > > > > > > I was having a lot of difficulty hoisting the main so I lubed the > > entire track, the cars on the main and checked for obstructions on > > the way up. I went all the way up to the top to see if there were > > any obstructions up there like maybe the halyard jumping off of > > the sheave or maybe even a broken one. Because of the difficulty > > in hoisting me on the main halyard, I decided to come down and go > > up on the jib halyard. I had the same problem. Both halyards move > > up and down effortlessly, without friction, but the moment there > > is any load, it takes tremendous energy to pull them up. All of > > the sheaves spin freely and are intact. I lubed everything at the > > masthead and cannot figure out why they aren't working properly. > > The halyards are rope and obviously internal and appear to be in > > good condition. > > > > If anyone has experience with this or any ideas on what to do, I > > would really appreciate them. > > > > Thank you, > > Michael > > > > > > > ________________________________ This e-mail and any files transmitted with it may be proprietary and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error please notify the sender. Please note that any views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of ITT Corporation. 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