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Laser 5000, where are they?!

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Iain C View Drop Down
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Post Options Post Options   Quote Iain C Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 3:42pm
Just re-read my post. The essential carbon sticks I was referring to are tiller extensions, not masts!
49er GBR340 "20KSB"
Sabre 27 "Summer Girl"
Foiling Moth GBR4093 "Beermoth"
1965 Flying 15 K797 "Braveheart"
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laserboy404 View Drop Down
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Post Options Post Options   Quote laserboy404 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 4:26pm
Iain, thanks for that, great post, certainly throws up the 49er as a very real option, just a matter of hanging on and seeing how often they come up for sale at that sort of money!

Not particularly keen on a rat/frankenboat, as it'd be good to be class legal in some form for racing purposes!
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craiggo View Drop Down
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Post Options Post Options   Quote craiggo Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 7:03pm
My old 49er was number 055 and when I got rid of it it was in great condition even though it was an older hull. It had been fully re-conditioned and brought up to new boat spec. As Iain says, they can be got for small amounts of money and the squad guys are always willing to sell sails and rigs on cheap when you need to replace bits. The rope work needed is not overly complex, the only thin I replaced was the halyard tail. Check the wing tracks are secure and you'll be fine. They got damaged by people trying to hang on to the wing as the boat inverted!
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Do Different View Drop Down
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Post Options Post Options   Quote Do Different Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 8:15pm
For JimC. Gone off thread but hoping you are still reading.
I could learn something here, ref stringing vs hiking.

My single wire, single spreaders two man boat. Light to low medium breeze going upwind, what is going on with the rig from us both sitting on the side me hiking vs the crew on the wire and me helming from leeward. I've heard people say the rig "works better loaded" I think it feels more powerful but it's hard to be sure.  
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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 9:09pm
Look at the mast!

If you consider a fairly ordinary hiking boat with a single spreader rig then most likely its got spreaders that deflect the shrouds out two or three inches, and going upwind probably the leeward shroud goes roughly slack while the windward shroud has tension equal to double the static rig tension plus the righting moment of the crew.

So thinking about sideways bend the top mast bends off and so the middle tries to bend up to windward. At the hounds the windward spreader is trying to push the mast to leeward with the bowstring effect from all the tension in the windward shroud, and the leeward spreader is doing nothing because the shroud is slack.

The result is that the mid mast is stopped from bending to windward, which restricts the amount the topmast bends off.

OK, now consider the same boat with one person on a trapeze. The vast majority of the righting moment is now down the trapeze wire, and thus bypassinng the spreader. In the old days of soft rigs I'd even see the windward shroud slack, which I can't quite explain, but neverless it happened. The leeward shroud, on the other hand, is now moderately tight what with the static rig tension and so on.

OK, so what's happening to mast bend now. Well, that windward shroud is slack, so there's no bowstring effect on the spreader and the spreader isn't stopping the mast bending to windward. Worse than that, the leeward spreader is now doing something from the bow string effect from the admittedly much less tight lee shroud, so that's trying to bend the mid mast to windward even more.
Net result, probably the top mast is a good 6 inches further to leeward than it was with no-one on the wire, which means the leech is more open and less power.

So what do we do about it?
The first option is what Bethwaite did with the Laser 2 and Clive did with the RS600 - ditch spreaders and use diamond stays. The load on the diamond spreaders doesn't vary with the crew on or off the wire and the rig behaves consistently.

The next option is to wind on the rig tension. I think the first people to really find out about this stuff were 470 Olympic sailors, and they just wound on the rig tension so there was so much static load the spreaders worked more or less consistently because the bowstring effect didn't vary much whether or not the crew was on the wire. The big disadvantage of this was that the polyester/chopped strand may 470s of the time lasted about 3 months under this sort of load until the hull went soft.

Another option is low down bend control, mast gate or lowers. Because they really stabilise the bottom of the mast the spreaders were a bit less important in controlling mast bend, so that helped too.

Yet another contribution is the push kicker. I'm no great fan of these, because I think they push in fore and aft mast bend where you really don't want it, but what they also come with is lowers to much higher up the mast than the effect of normal lowers and mast gate, so that stabilises the mast too.

So if you can follow a single string boat up a beat and watch the mast and leech as the crew gets on and off the wire, well you'll probably see a lot of this.

Which one is best - well probably all of them together. But as much rig tension as is safe for the boat in question is rarely a bad thing. It can be very instructive though to look very closely at the boat when you put the tension on. I remember one boat where the foredeck would gain a ripple as the shrouds were wound up to what was fast because the boat had bent so much!

Edited by JimC - 05 Sep 14 at 9:11pm
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Do Different View Drop Down
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Post Options Post Options   Quote Do Different Quote  Post ReplyReply Direct Link To This Post Posted: 05 Sep 14 at 10:30pm
Ta for that JC. Something to think on. 
The effect probably not so pronounced on my foam sandwich boat with 180 odd kg on the shrouds.
I guess it explains why my old Contender "died" on me every time I went out on the wire until I fetched the book out and got serious. 
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Henry110 View Drop Down
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Post Options Post Options   Quote Henry110 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jun 20 at 10:20am
Hi i have a laser 5000 and trailer rod for sale? 
Henry
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Henry110 View Drop Down
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Post Options Post Options   Quote Henry110 Quote  Post ReplyReply Direct Link To This Post Posted: 16 Jun 20 at 10:23am
Hi i got one laser 5000 on rod trailer?
Henry
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