Hi all,
Just wondering if anyone has put a kite on a wooden boat.
Just wondering how much pressure is put on the hulls when the kite is up?
Cheers
William
nswmossie.com 1635

Hi William

Here's a few:









"Red Alert" was a very light ply construction Mozzie, built for cat rig only with twin forestays. It was changed to a high bridle configuration and was able to handle it.

As far as the loads on the boat go, the loads on the bows from the spinnaker are not as much as you get from the forestay bridle sailing upwind. It is nothing like the effect of a gorilla with a 10mm mainsheet and a six-to-one purchase.

There is some extra load where the beams are attached to the hulls as these get twisted forwards or backwards every time you gybe. Having said that we have seen no problems after 5 seasons of spinnaker use (and the South Africans have been doing it much longer than us - with 100% timber boats to start with).

Hi Will
I had Ree alert with a kite for a number years and i had no trouble with it.The only thing is to have a bridle on the boat and not two forstays ,if it is setup for sloop there is <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" /> no problem
Peter N

Hi all

I was discussing the idea of a kite for my boat with the boat builder who did a recent repair.

He was rather dubious about stays for the pole being fixed to the bows given the lightweight construction and "strongly" suggested that if I was to add a kite, I should stay the pole to the chain plates.

Does anybody else do this and is it a workable alternative to not having a kite at all?

I'd love to try one but having just got the new paint job done and everything ship shape, I'm not overly keen on breaking her.

Cheers

I have recently broken a bow off my wooden mosquito. It was while sailing upwind, sloop rigged, in maybe 18 knots and a bit of chop, twin trapeze.

My personal opinion is that more pressure is put on the bow in these conditions from the extreme tension on the forestay and jib bridle than when under spinnaker with the pole bridle to the bow tips.

Apparently some of the timber mosquitos were built as purely one-up boats with twin forestays and no structural allowance for the extra side force on the bow from a bridle forestay arrangement.

My advice, if you're keen to do it, is to keep the bridle as high as possible, without interfering with the operation of the kite.

I can't see a problem with the pole bridle going back to the main beam, there should be plenty of angle to keep it under control.

Thanks for your thoughts.

I'll do a few sums on angles and a bit of trial and error.

As next season will be my first full one on a mozzie I was planing to leave it a while but the sight of mozzies in full flight with kite is proving to be a strong temptation. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Back in the early days of the spinnaker development I did have the pole stayed from the bridle chainplates initially. This works ok but the angle from the chainplates to the end of the pole is too sharp and you will probably damage the chainplates (tearing them forwards) by doing it that way (they are only built to handle upwards and inwards forces).

Better to take the stays from the bridle chainplates to some point on the pole between the chute mouth and the end of the pole and accept that the pole will bend some when it is under load. If you are using a windsurfer mast (as most of us do) use the bottom end rather than the top and it should be strong enough.

When you rig the pole this way you may find you need to add some "dummy" stays from the end of the pole to the tips of the bows - you can use bungee to avoid loading the bows. This stops the spinnaker sheet dropping over the bow and under the boat when you are taking it down. Try it first though. If your sheets are the right length you may not have this problem.

Having said all this, "Red Alert" was a light plywood boat with twin forestays, but the spinnaker pole stays on the bow tips didn't cause a problem for that one.

Twin forestays don't work with a spinnaker though - it had to be changed to a bridle setup. To avoid loading up the hulls a fairly high bridle was set up, with a fake bridle below it to support the chute and the pole.

Like this ...........

Thanks Tim,

That's pretty much the way I was heading but its good to know it's been done before.

I don't think a bit of bend in the pole will matter.
When sailing a B14 last season I noted that the extendable poles on them used to bend quite a bit in a blow . Didn't seem to cause any problems.

Lots more learning to do <img src="http://www.catsailor.com/forums/images/graemlins/confused.gif" alt="" /> before fitting the "turbo-charger" but I'll start collecting the bits and pieces required and probably treat myself to a kite from Santa.

Thanks for the advice.

Just finished competing in the Sauna Sail with a 25 year old wooden boat fitted with a kite (sail number 768). Normal single bridle, old mirror dinghy aluminium mast cut down to 3030 mm and using 3 mm spectra as stays. I fitted steel tubes in the bow holes to stop chafing the ply and large washers to spread the stay load. Bow doesn't flex more than a cm and the whole boat can be picked up by the pole. Prior to going spinnaker I did replace the decks (cracking ply) but that was just old age nothing to do with the spinnaker. I had the knots in the spectra stays let go but that's much better than breaking a bow. Must say Tim's advice in how to sail was more value in not stressing the boat. I'd check the condition of the hulls and decks forward of the main beam.