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Tipster1947
Joined: 07 Jun 2009 Posts: 8
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Posted: Wed Aug 19, 2020 11:15 am Post subject: Boom slides down and mast protection |
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Boom Slipping
In spite of tightening clamp as much as I dare, my vintage Windsurfing Hawaii booms with rubber shims are sliding down RDM masts. Would light sanding of masts would make them LESS slippery?
Mast re-coating
Someone suggested that the area where mast gets most wear is boom clamp on area and suggested re-coating. Which would be appropriate, polyurethane or two-part epoxy such as West system?
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mac
Joined: 07 Mar 1999 Posts: 17748 Location: Berkeley, California
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Posted: Wed Aug 19, 2020 11:49 am Post subject: |
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Go to a bicycle store and get a damaged inner tube for a mountain bike. Cut a 6" piece and roll it onto your mast under the boom. Problem solved. |
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Ugly_Bird
Joined: 04 Nov 2008 Posts: 335
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Posted: Wed Aug 19, 2020 12:58 pm Post subject: Re: Boom slides down and mast protection |
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Tipster1947 wrote: | Boom Slipping
In spite of tightening clamp as much as I dare, my vintage Windsurfing Hawaii booms with rubber shims are sliding down RDM masts. Would light sanding of masts would make them LESS slippery?
Mast re-coating
Someone suggested that the area where mast gets most wear is boom clamp on area and suggested re-coating. Which would be appropriate, polyurethane or two-part epoxy such as West system?
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I wouldn't sand the mast. The problem seems in the incompatibility of the mast and the clamp/shim. As was already suggested, another layer of rubber could help. I had similar problem with Naish 90% carbon SDM and Fiberspar carbon boom. Used random 5 mm thick rubber sheet to beef the clamp up. |
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dhmark
Joined: 04 Sep 2007 Posts: 376
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Posted: Wed Aug 19, 2020 5:24 pm Post subject: |
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What is slipping? I think you are describing that the shim is slipping down the mast, but the boom is holding the shim OK. Some shims are not very flexible or sticky and hold their pre-molded shape too well. Your boom clamp has to squeeze against the resistance of the shim. Maybe change the shim. The best shims I ever had were home made out of thick transparent flexible (vinyl?) plumbing hose that has criss-cross fiber imbedded in it, the diameter was just a bit smaller than the RDM mast, maybe 1/4" thick, so that when you cut it open, it fits around the mast with only a small gap. Very tacky on both sides, very flexible but not compressible. Found it at hardware store. Cheap too.
Last edited by dhmark on Thu Aug 20, 2020 8:58 am; edited 2 times in total |
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pmlct
Joined: 02 Mar 2010 Posts: 68 Location: Middletown CT
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Posted: Thu Aug 20, 2020 8:48 am Post subject: |
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I also have an older WH boom and I recall it slipping as well. I haven't used it very much. Also regarding RDM shims, I find that one brand slips more than a different brand, without mentioning who makes what. So far I am just clamping everything really tight, when using my older booms. |
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isobars
Joined: 12 Dec 1999 Posts: 20935
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Posted: Thu Aug 20, 2020 10:49 am Post subject: |
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I've seen masts, including brand new ones, get crushed simply by over-clamping. They may collapse as you close the clamp (if you think you heard a subtle crunch, you probably did), while the rigged sail lies on the ground (if it starts to quiver in no wind, it's breaking up), and a mile offshore in light lake conditions. I recommend fixing the problem with friction, not brute force.
As dhmark suggested, PVC reinforced vinyl hose, available in many sizes and wall thicknesses from many sources, works great:
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Fri Aug 21, 2020 9:11 am Post subject: |
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The pipe is what was used prior to dedicated made to fit shims. As I recall 20 years ago it worked. Some of the new booms are SDM/RDM compatable remove the inner sleeve for fat masts.
The sleeves , a separate unit work best, and my AL360s recommend their use, but with Many Chinook and others throughout the years I’ve never encountered a problem
Course never had a flat tire on a Ferrari either. _________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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swchandler
Joined: 08 Nov 1993 Posts: 10588
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Posted: Fri Aug 21, 2020 7:13 pm Post subject: |
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These days, separate dedicated rubber/composite shims are made by many mast and boom manufacturers. I have ones offered by Maui Sails and NoLimitz that work perfectly, particularly with RDMs. It's not like they are too expensive or difficult to use. Frankly, I like the idea of using a boom front end that is designed for SDMs, and using a RDM shim when using RDMs. While some may disagree, I think that designing a boom with an adjustable SDM/RDM front end ultimately results in attachment compromises. Keeping everything together is simple by keeping the shim incased and enclosed in the front end after every usage. The only downside is matching up the shim after using an SDM mast. |
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Ugly_Bird
Joined: 04 Nov 2008 Posts: 335
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Posted: Fri Aug 21, 2020 8:01 pm Post subject: |
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swchandler wrote: |
NoLimitz that work perfectly,.
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I have exactly opposite problem with this one. NoLimitz shim with NoLimitz RDM. So much friction. Even when unclamp the boom can barely slide that up and down the mast to adjust the boom height.
Andrei |
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Ugly_Bird
Joined: 04 Nov 2008 Posts: 335
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Posted: Fri Aug 21, 2020 8:01 pm Post subject: |
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dup |
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