Wing Mast

[JimC]

Monday, when pulling the boat breaker on, there was the unmistakable sound of carbon splintering,

How much rig tension are you using? With the old school setup with diamonds controlling lateral bend there was no need or even point in having boat breaking rig tension. But those rigs had hounds hoist kites of course.

Sorry to have missed your PM for the weekend. Oddly I half considered bunging the Bethwaite mast on the van roof and wandering over, but then thought, no, no point in boring people...

[RobinJones]

Sorry, I never got round to replying!

I'm not using the mega amounts of rig tension most are - about 115kg on the forestay, if that at a guess. It still does not sag either under kite load or when going upwind, which is how I've been trying to set it, as low as I can whilst still keeping the forestay from sagging. the way the rig is set up, the leeward spreader never does anything upwind (this diamond is slack owing to the spreader swinging backwards, and the windward spreader induces slight windward bend in the mast, as it swings forwards), so I see no reason for mega rig tension.

It's had good moments and bad, but it doesn't actually seem to be more difficult to sail upwind than any other rig I've used on a cherub yet. Don't have to play the main anymore than usual I don't think. The good moments have seen some blistering speed, notably in strong winds upwind, but i have real trouble making it rotate far enough in power hunting conditions. I cannot run enough tension in the caps to actually do anything useful without seemingly restricting the rotation possible, and as such i'm getting rid of the whole swinging spreader/mast head support idea, and am going to try the whole set up with diamonds within the shrouds, and an unsupported tip (just a scaled down A Class rig). Very worried the kite will break the mast, but hoping for the best, and its no major loss even if it does snap.

The ex-riot van sail that I recut is as yet the best setting sail I've had on it - tried 2 different cat sails (thank you Alex!) one of which blades off way too easily, and the other which has the opposite problem. Planning on recutting the one that blades off too early to allow the head to hook a bit, and use a pair of tapered battens in the head to try and encourage any depth.

Probably won't be used at the nationals this year, but still not quite decided there yet.

(No worries Jim - perhaps when we head back to QM this autumn! )

[JimC]

Perhaps some sort of caps arrangement where you can utterly dump all tension in lighter stuff, but pull it on when needed? As I dimly recall my experience was I needed the full range of tweaking upwind, but downwind I only cared about keeping the mast above the hull and in one piece.

[JP233]

A heigh field/death trap/child scaring leaver thing.

[JimC]

If folk would like me to sling the ex Nicola Bethwaite Cherub wing mast on the van roof and turn up at QM so they can take a look at it let me know (and agree a time!)

[pratn0]

I'll be interested.

[kerrgreg]

Me too

[RobinJones]

As a little update on this, in case anyone is still interested;

Banshee retains her wing mast, and will do for the forseeable future - in the same set up she's had for about a year now (swinging spreaders, rotation control running along the top of the boom, manually tacking the mast).

Generally I run full rotation on the mast, which gives me some very good upwind speed and pointing - better than I ever had with a conventional rig. When it gets windy, it is possible to depower by centering the mast, however the main gets very heavy, and its exceptionally difficult to tack in these conditions due to the weight high up, and the crew having to pause mid tack to push the mast across.

Downwind, there is a slight loss of speed I feel. Due to the kite loads, and shroud base being narrower than on a catamaran, I cannot get as much rotation as I would like, however, after a few runs beside Ronin/Dans boat/Shiny on the Sunday at Rutland, I can confirm that I'm not terrifically slow.

I have 2 sails I use at the moment; an old F16 catamaran sail, and a cherub sail that has been re-cut to have 40mm, rather than 190mm of luff curve. the F16 sail, though excellent condition is very slow unless its excessively windy, as I don't have the 16:1 mainsheet that it would have been designed for to pull leach tension on. The re-cut cherub main at this point is surprisingly fast, and requires less kicker than I would have used on a standard rig. I'm planning to re-cut another similar main to this as soon as possible, as the cherub main is very much a beta stage main, and exceptionally tired/holey.

At this point in its development, I think there are far greater things holding me back than the wing mast, and it has boosted my overall performance; its pretty much a trade off of straight line speed upwind, which is now excellent, against tacking.

I will be keeping this rig on banshee, however, any new boat I make will have a more conventional, non-rotating rig - mainly owing to how bespoke the whole of this set up is, and I wouldn't want to go through the making of one again.