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Laser Top Mast Changes |
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Fraggle 
Far too distracted from work 
Joined: 28 Feb 07 Location: United Kingdom Online Status: Offline Posts: 220 |
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 Topic: Laser Top Mast ChangesPosted: 28 Nov 08 at 4:05pm |
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Old broken top sections can relatively easily be turned into booms.
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Laser 173312
Far too distracted from work
Joined: 08 May 07 Location: United Kingdom Online Status: Offline Posts: 416 |
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Posted: 28 Nov 08 at 3:50pm |
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Gary The idea of a carbon top mast has been 'put on hold' the moment and whilst I take your point about the work hardening I still think the top section would last much longer without the rivet forcing you to put the 2 parts together in a specific allinement. It also means you can end for end it each time you sail and so spread the wear about. Also thinking a little more about it, now you can use tape around the mast joint. You would be able to tape the collet to the LOWER section semi permanately and just slide which ever end of the top mast came to hand first into it. I agree that the sail probably won't change for a few years yet, but this could be introduced relatively quickly I would hope. Incidently what do most people do with their old tubes. Do they just throw them or can they be recycled. May be PS could give you a discount for PXing your old tube for a new one. They might not need so much raw ally if they did that and that would be good for the environment. Sorry that's a daft idea 'PS giving a discount' I mean. Edit There seems to be some confusion about this. I don't think the top section is changing at all. As I read it all that will happen is the 2 collars will be taken off it and replaced by a split plastic cup that the top section will rest in. Please correct me if this is wrong.
Edited by Laser 173312 |
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Matt Jackson
Really should get out more 
Joined: 21 Sep 04 Location: Darlington Online Status: Offline Posts: 962 |
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Posted: 28 Nov 08 at 3:20pm |
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Sorry I disagree, if I remember correctly the mast always goes together the same way and in time bends in effect giving some pre-bend which changes performance. If the new system allows the mast to be put together any way then there will be less bend and less change in performance. Therefore the change will affect the performance of the boats with the new top section. Notice I didn't say whether performance will be increased or whether the change is a good thing or not - I just disagree the the asertion. |
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Laser 203001, Harrier (H+) 36
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Jamesd
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Joined: 01 Feb 08 Online Status: Offline Posts: 377 |
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Posted: 28 Nov 08 at 1:13pm |
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they have been toying with composite ones for ages. Not sure if it is for all classes but was aimed at the radials and reducing the weight range for the boat. i presume by making it lighter and therefore less moment, as the bend characteristics are to remain the same as the ali, not to sure though. but the development has been postponed. crap idea though. Imagine a carbon top mast or glass for that matter from laser. they would want £600 |
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alstorer
Really should get out more
Joined: 02 Aug 07 Location: Cambridge Online Status: Offline Posts: 2899 |
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Posted: 28 Nov 08 at 12:53pm |
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Furthermore, for a piece under tension, if the hole is filled tightly by, say, a rivet, you actually see a further decrease in strength as the deformation of the material around the hole is adversely affected (but in compression, the rivet will take some of the force). |
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Guests
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Posted: 28 Nov 08 at 12:42pm |
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It'll be interesting to see if this does reduce breakages. The mast will still bend but by rotating the mast the user can spread the bending over 360 degs...do that to aluminium and it will still break......
I would have thought making it out of a different material would be a better bet...same flex characteristics as ally but one that doesn't work harden. (please consider my sig when reading this Edited by GK.LaserII |
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Alistair426
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Joined: 02 Jun 08 Location: Vatican City State Online Status: Offline Posts: 201 |
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Posted: 28 Nov 08 at 12:40pm |
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Certainly is...lots of people do it. Doubles the life of the top-section...especially if it has already been straightened a couple of times.
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Jamesd
Far too distracted from work
Joined: 01 Feb 08 Online Status: Offline Posts: 377 |
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Posted: 28 Nov 08 at 12:33pm |
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i did read inthe latest laser mag, the measurer going on about recommending end for ending the top mast section. is this legal?
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Jamesd
Far too distracted from work
Joined: 01 Feb 08 Online Status: Offline Posts: 377 |
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Posted: 28 Nov 08 at 12:31pm |
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you cannot make a hole in something that is acting in tension. it creates a weakness that will fail. a bit like trying to rip something, its alot easier to rip a shirt if you make a small cut with some scissors. the rivet on a laser top mast is there to hold the plastic sleeve at the bottom (the black thing about a foot up from the bottom), that is its only purpose. If you put the top mast in with the rivet facing backwards, then most of the time the rivet is in compression which is fine, but bear away downwind in strong breeze and you can find the mast bending forwards towards the bow (this happens alot if the boat is going slowly, i.e. hitting the back of a wave) the back edge of the mast is now in tension and so is the rivet hole and thats when the problem occurs. What they are suggesting is a collet. basically a shim that will fit in the top of the bottom section which will do the same job as the sleeves on the top mast, suppot the top mast within the lower. This will have no effect on the mast stiffness as the added material (i presuming there has to be some) will have no contrabution to the stiffness of the lower section as there is next to nothing in terms of BM at the top of the lower section. Its a very very good idea and much needed, my only fear is that laser preformance will not back it as they will lose sales on spares and lets face it, they are greedy sods. |
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Guest
Newbie 
Joined: 21 May 04 Location: United Kingdom Online Status: Offline Posts: 0 |
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Posted: 28 Nov 08 at 12:23pm |
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To stop the top mast sliding inside the bottom mast there is a collar on the top mast held in place by a rivit. The rivit is a weak spot and so the top mast is always put in the same orientation leading to shorter life. I believe they will stop the top mast sliding down the bottom section with a boot in the bottom mast such that no collar is needed on the top mast and as such no rivit which means the top mast can be put in in any orientation leading to longer life. A very sensible refinement with no performance change |
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