Laser 5000, where are they?!

Hi i have a laser 5000 and trailer rod for sale? 

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

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!

Just re-read my post. The essential carbon sticks I was referring to are tiller extensions, not masts!

How much is a bottom end RS800 now to buy, too?