You can correct this by lowering the tip of the spinnaker pole by shortening the rigging. We went through a period where the spinnaker luffs got longer on the Nacra 20 and we ended up with so much prebend on the poles that they would break if you looked at them wrong. I ended up rigging the middle part of my pole to extend it lower at the forstay bridles so it wouldn't have to have so much prebend.
If leaving the spinnaker sheeted through the puffs helped with boat control, you are probably over sheeted...which is not fast. That said, it is good to keep the spinnaker properly trimmed through the puffs and not ease it to depower it unless "all is lost!". Fix the spin luff issue and you'll find the boat will be very different downwind.
mast needs to rake further forward but that will only give you more issues with the spinnaker luff, so lowering the pole is about the only option you have. it does look to be sitting high in the bridal
did you photo-chop the pic ???
someone has shot a bloody great hole in the middle of your boom !!!
Yar, & this ere post be done without a sin'le drop o' rum passin' me lips
Kingy started with Impara Cadet #3 / Mosquito #245 & now Mosquitos #1182 & #1740
LOL Kingy, looks more like a white paddle strapped to the boom to me.
Spin pole has to come down, no way around it. looks like you have plenty of room to move, just put a small rope loop around the pole under the bridal to facilitate.
Ok, everybody seems to agree on the pole :-) But the loop is already in place, so that would mean to shorten the rigging? Just to be absolutely sure (do not want to make more damage the necessary) please see the below pic. Is this the way to do that? (please do not look at everything else, this is an old picture with old snuffer bag, without self tacker, and with totally different setting)
Please enlarge the picture (right mouse button) to read the text
Maybe a stupid question, but why not move up, by replacing the "spi bracket" (how is the thing called up in the mast?)
And pirate, no did not photoshop ;-) Indeed there are two paddles there which were obligated with a long distance race (Texel), and we've never took them off, after.
Ok, it is important not to tamper with the length of the wires labled "shorten these?" under any circumstances. the bridal wires are set at a structural length, any shorter and there will be a greater load on the bows pulling inwards. you don't want to stress your bows more than you have to.
so the "ladder" or chainplate shouldn't have to move at all. unless your not happy with your mast rake.
the wires "what about these" they are the whiskers, (very feline aye) are exactly what you want to shorten. by the looks of the previous photos your coming down about 150mm/6in which will be a lot of bend in the pole, if your worried about breaking the pole then you can suspend the pole below the bridal to make it straighter. does that make sense or would a photo help?
and no you cant raise the height of the spin bracket (spinnaker bale) because it is set a height not to break the top of the mast off. its a safety thing.
You need to shorten the "what about these". You may need to tie another loop at the bridles under the one you already have. The forestay and bridles need not be changed.
Ok, I think I understand! And all explanations are sounding reasanable (however the drawing by Jake confuses me a bit)
So by shortening the whiskers we should drop the pole between 15 - 20 cm (what we measured). The pole is indeed already under a lot of bend stress, so this would mean that we should tie another rope loop underneath the original one(and maybe when it turns out to be the right solution and place, I can weld one)
Jake, The only thing I do not understand right now, are the two lines from the bridle you have drawn? As I understand correctly the bridle wires stay in place?
The red lines in Jake's drawing are new wires/lines used to support the spin pole. They originate from the same eyes on the hulls, but do not attach to the forestay. Don't move the bridle wires for structural reasons.
The red lines in Jake's drawing are new wires/lines used to support the spin pole. They originate from the same eyes on the hulls, but do not attach to the forestay. Don't move the bridle wires for structural reasons.
Exactly. If you extend the pole much farther than you already have it mounted below the furler, the middle of the pole will start to swing side to side as the spinnaker pulls the pole sideways. These baby bridles help keep the middle of the pole centered. They will also help the pole survive if you pitchpole with the spinnaker up. If the bottom of the spinnaker enters a wave it will push the pole rearward and the middle will flex up and snap.
Ok, now it's clear! Thank you all for great support. This will take a while before we have tried this (and it's also a little bit winter here), but I will let you know!
Also you can remove the wires that go to the end of the spinnaker pole and replace them with Dynema line until you think you have the length right. I just shortened the wires quite a bit and have a small length of Dynema on each side to make the adjustment.
Mike makes a good point there too. On our boat, we have dynema (Samson Amsteel) pole bridles that have a large eye splice on the hull end. That eye splice has a very long tail that tucks into the line and comes back out again after about 10 or 12". You can use that extended tail to adjust the length of the bridle. To secure it, you just tie the tail around the line.
It was some time ago, but in the meantime we've adjusted our boat (as suggested by you), and brought the spinnaker pole around 20 cm's down. Indeed the spi is a lot flatter, and yes we drive it deeper now, which means less agressive corrections. So once again: Thank you all for the help! Furthermore we've adjusted the mast rake a bit, and found out that the spreaders were not equal. So we corrected this.
Sunday we had some nice weather (16-20 knots) and made a short video:
I agree as you say that it still looks a little round, however I think this is also the video. We see (and experience) it's a lot flatter.
Still we have one last question. To keep everything in control, basically we drive our spinnaker most of the time sheeted in rather tight. (maximum sheet length between the boat and the spi is 1 meter) However we were more or less overtaken by another boat (very good sailors who were doing a racing track) who had the spi very "open" and more in front of the boat. It looked very fast and also in control. We tried to do the same, but as I tried it collapses every time. We have to keep it more or less in line with the jib.
Can anybody explain this? We still have to learn a lot about spinnaker sailing especially at 16 knots and up.
Pull the tack line fully in. Looks like there are 3-4cm of luff tension to gain there
More luff tension allows you to sheet the spi out more to go faster and deeper (to a certain point at least).
If you do the "grab the luff in your fist and twist it" test. How far can you rotate your fist? 45deg? 90deg? More?
Hwo did you set the luff tension line inside the spi luff? On a new spi I hoist the spi with a slack tension line, then tension it about 5cm.
When sailing with a spi, it is very easy to sheet in too far and close the leech. The leech needs to be open and complement the mainsail trim for optimal speed. The rule of thumb is to sheet out as far as you can, until the luff curls, at all times. Only experience will tell you when you are on the optimal course. If another boat walked over you, try to replicate their setup
An old spi will become deeper as it ages and is used. A new spi is flatter and faster. If those other guys had a new spi and your spi is well used. Well..