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Questions for spin gurus

Edchris177

Rank: Chief

Registered: Nov 26, 2009

Last visit: Aug 10, 2024

Posts: 2531
Posted: Aug 06, 2014 - 07:13 PM

I've launched the kite from my 20'x10' beast 8 days now, 6 of them solo...lots to do when solo, so I've mostly furled the jib when the kite is up. This day was pretty light wind, & a big crowd on board, but one guys wife chased up in a Seadoo & took photos.

Couple of questions regarding setup & trim.
In this photo you can see the foot of the kite is horizontal, due to the angle of the spin pole. I know from monohulls they "open or tighten" the spin by allowing the pole to rise, or winch it down.
Is there a rule of thumb, or a "standard" angle for the pole, considering you cannot control it on the fly as is the case on the monohulls?
Also, you can see that the telltales on the main are flying, but I have often seen them not in trim. How far can you safely travel out to trim the main without jeopardizing the mast?

In the image above you can clearly see the sheet angles, going to the ratchet block on the rear beam. Most people seem to locate the blocks on the stay adjuster. As you can see, that would change the angle considerably, & pull the clew down more than stretching it rearwards. Which is better, or does it depend on the cut of the spin?
Lastly, how tight should the lines be from the end of the pole to the bridal tangs? I have seen photos showing the pole bent downwards. My pole is 2" aluminum, & takes quite a bit to bend it downwards. Should these lines be tight as in tighter is better, or just snug, or does it matter?
We used to play the end of the pole on the monos, throug a fair bit of arc, depending on the apparent wind, but you can't do this on the Cat.

--
Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Aug 06, 2014 - 09:44 PM

Quote"open or tighten" the spin by allowing the pole to rise, or winch it down.

that can be controlled with the spin halyard - but i can't think of a time when i adjust that. I like my spin luff set the same in just about all conditions (it's all off the wind....)

QuoteIs there a rule of thumb, or a "standard" angle for the pole, considering you cannot control it on the fly as is the case on the monohulls?

the pole angle doesn't matter. what matters is
a. that your pole isn't so low that the snuffer/sock doesn't scoop water when running down a wave
b. your pole angle will directly effect luff tension. so that is a HUGE factor. On all sails you need luff tension. most modern spins a good starting point / rule of thumb is you should be able to grab your luff and turn your hand 90-180 degrees. this was an old method but still a decent starting point. once you start to set it the same all the time, you can make small adjustments and see what works best for you.

QuoteAlso, you can see that the telltales on the main are flying, but I have often seen them not in trim. How far can you safely travel out to trim the main without jeopardizing the mast?

i dont care much about my main tells with my spin up. but you can travel out a good amount (1/3 - 1/2 way) without any issue in light and med air as long as your still sheeted fairly tight (leech is still acting as a backstay). In very light air i will loosen my main a little and travel out a bit, but in most situations having it centered is good (and easy since i dont have to touch the main/travler sheets at all)

Quote As you can see, that would change the angle considerably, & pull the clew down more than stretching it rearwards. Which is better, or does it depend on the cut of the spin?

depends on the sail. the old mystere symmetrical sails were huge and had to be run to the rear beam. all the mysteres around here run tornado asymmetrical spins that are not as huge and can be run to the sidestays

QuoteShould these lines be tight as in tighter is better, or just snug, or does it matter?

TIGHT! you want to bend your pole down a fair amount (and you should have a loop under your furler to help pull the middle of the pole up) - the bend is needed to avoid your pole from inverting (bending upwards) during use. this would / could cause several issues: it could invert, revert, invert, revert during use and thats not good. plus it would be lengthening / shortening / lengthening ... the pole which could cause crazy wear on your spin attachment points, not to mention you could possibly break off a bow tip (where the bridal runs through) with all that craziness..

PS the cat looks great!

Edited by MN3 on Aug 06, 2014 - 09:48 PM.
nacra55

Rank: Mate

Registered: Nov 02, 2004

Last visit: Aug 07, 2023

Posts: 626
Posted: Aug 07, 2014 - 12:24 AM

[quote=MN3]
Quote

QuoteShould these lines be tight as in tighter is better, or just snug, or does it matter?

TIGHT! you want to bend your pole down a fair amount (and you should have a loop under your furler to help pull the middle of the pole up) - the bend is needed to avoid your pole from inverting (bending upwards) during use. this would / could cause several issues: it could invert, revert, invert, revert during use and thats not good. plus it would be lengthening / shortening / lengthening ... the pole which could cause crazy wear on your spin attachment points, not to mention you could possibly break off a bow tip (where the bridal runs through) with all that craziness..

I'm no grue. but in the second pic, you can see the loop of line under the furler. Tightening the lines would bring the pole down and tighten the luff.

I like a set of tell tails on my spin. Helps me get the spin and jib working the same. From the tack, 1/4 to 1/3 up and 18-24 inches back.

Solo on a 6.0 w/ a tramp launched spin, your the man.

--
Ron
Nacra F18
Reservoir Sailing Assn.
Brandon, Mississippi
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bacho

Rank: Mate

Registered: Jun 17, 2011

Last visit: Sep 24, 2023

Posts: 783
Posted: Aug 07, 2014 - 04:35 AM

You want at least a little pre-bend in that pole. Probably more than you have there. The amount of bend is not all that critical, we would adjust it to achieve better luff tension. Hoist you kite all the way up, I would want it to be able to tighten past the 90* twist that was mentioned. If it's too loose, add a little more prebend. Then you can make a mark on your halyard that will be close to the clearing point at "proper" tension. You can adjust it in and out from there, but it will give you an idea of what's going on.

Keep driving the main, I used to sheet it tight and forget about it. I found serious speed when I started trimming it. Don't travel out unless you need to de-power. Let out enough sheet to get the tells flying. I probably pull in 4-6 feet of sheet every time in return to an upwind sailing trim just to give you and idea. IMO, these masts are a little tougher than some make them out to be. Also let the mast rotate all the way out, if you have a positive rotator, use it to point the rotator bar straight down the beam.

--
Greenville SC

Offering sails and other go fast parts for A-class catamarans
--
MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Aug 07, 2014 - 07:13 AM

QuoteI like a set of tell tails on my spin. Helps me get the spin and jib working the same. From the tack, 1/4 to 1/3 up and 18-24 inches back.

that is fine with a selftacking jib (and many of those dont furl) but none of us use all 3 sails at the same time
P.M.

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Posted: Aug 07, 2014 - 08:27 AM

Like Andrew said, don't focus too much energy on the main. Sail the angles hot downwind. Focus on the luff, sail just on the edge of the luff curling. Tiller and the spin trim are a teamwork thing. Hit that apparent wind, then it's magic, just keep it in the grove.

--
Philip
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Edchris177

Rank: Chief

Registered: Nov 26, 2009

Last visit: Aug 10, 2024

Posts: 2531
Posted: Aug 08, 2014 - 07:39 AM

Thanks everyone.

Quotethe old mystere symmetrical sails were huge and had to be run to the rear beam.

The boat is a 2000, delivered to original ownerwin 2001, I don't think the kite is original. It looks brand new,(North Sails) & is non symmetrical.I measured it roughly as 28'x24'x17' not sure how that compares to a T spin. I think I'll try moving the blocks. I used a turning block on the front beam,(just because they were already there for barberhauler I think) to get better angles on the ratchet. Moving them would mean 15' less sheet.

QuoteI'm no grue. but in the second pic, you can see the loop of line under the furler. Tightening the lines would bring the pole down and tighten the luff.

I tightened them up quite a bit. The PO had hi tech lines with SS hooks to slip into the fitting on the front spreader bar, but they seemded about 6" to short, maybe they used a different spin pole. I used some Sta-Set that I saw in one of the original photos, but it seems to stretch somewhat. Under power the pole lifts enough that the loop under the furler shows some slack.

QuoteI like a set of tell tails on my spin.

I have one set, you can just make them out,top photo, hidden in the blue stripe along the leading edge of the sail.

QuoteSolo on a 6.0 w/ a tramp launched spin, your the man.

What's that saying about fools rush in.....?

QuoteThen you can make a mark on your halyard that will be close to the clearing point at "proper" tension.

Good idea. I have seen several instances of not having it up all the way. When solo you don't always hold the "no power" heading while finishing the hoist, & have to cleat & attend to more pressing matters! A few times I've had to steer DDW to finish the hoist, or do it while gybing the kite.

Quotesail just on the edge of the luff curling. Tiller and the spin trim are a teamwork thing. Hit that apparent wind, then it's magic, just keep it in the grove.

Yes, I'm discovering how subtle steering has a major effect on power. That groove is goddamned scary at times! I went out yesterday, with a forecast of max 10 kts, buoy showing 6. Rounded the point & was suddenly in pretty constant whitecaps.
I'm feeling pretty cocky, until I suddenly got in that groove. It took off like a cat shytting razor blades, then we were on one hull. OK, I enjoy flying a hull as much as the next guy, but downwind, with that kite pulling like a mule, & no idea if that hull was going to stabilize or keep going I took the wimp route & steered DDW , out of the groove, doused the kite, rinsed my shorts & waited for a calmer day. When I got back the buoy showed 15 gusting to 18 kts,(17-21mph).
What do you guys consider the safe wind speed? Those kites are pretty thin material.

Edited by Edchris177 on Aug 08, 2014 - 07:41 AM.

--
Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--
MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Aug 08, 2014 - 08:38 AM

QuoteI tightened them up quite a bit. The PO had hi tech lines with SS hooks to slip into the fitting on the front spreader bar, but they seemded about 6" to short, maybe they used a different spin pole.

I just noticed that your spin bridals don't go to your bow tips. this is the first time i have ever seen a boat like that. Please verify this is correct - looks like your pole is prime for inverting with that rigging.

PS - 6" short may be perfect when the pole is bent down -

QuoteI used some Sta-Set that I saw in one of the original photos, but it seems to stretch somewhat. Under power the pole lifts enough that the loop under the furler shows some slack.

I recommend a high modulus line and even then most have creep. I use dingy control line here (http://www.apsltd.com/c-7275-dinghy-control-fse-robline.aspx) with a trucker hitch style knot here so i can re-adjust as it creeps (has dynema core) but vectran claims to have no creep so may be a better choice (i only have to adjust this once every 12 months or so)

QuoteThen you can make a mark on your halyard that will be close to the clearing point at "proper" tension.

not sure i understand this.
why would you ever not hoist it all the way up?
bacho

Rank: Mate

Registered: Jun 17, 2011

Last visit: Sep 24, 2023

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Posted: Aug 08, 2014 - 09:20 AM

MN3,

All the way up would be max tension. That max tension will change with mast rake, creep on the synthetic lines, and how tightly he ties the head and tack of the spin. That may be fine for some boats, especially ones that rarely have their settings change.

I make a mark as to what is good tension for a normal day. Then if the mast is pushed forward or back, I have a reference point to go from.

Sometimes I will also loosen the luff up some if I am trying to carry the spin higher. It's just nice to have a reference point.

--
Greenville SC

Offering sails and other go fast parts for A-class catamarans
--
MN3

Rank: Master Chief

Registered: Jun 20, 2006

Last visit: May 22, 2024

Posts: 7089
Posted: Aug 08, 2014 - 09:37 AM

bachoMN3,

All the way up would be max tension. That max tension will change with mast rake, creep on the synthetic lines, and how tightly he ties the head and tack of the spin. That may be fine for some boats, especially ones that rarely have their settings change.

I make a mark as to what is good tension for a normal day. Then if the mast is pushed forward or back, I have a reference point to go from.

Sometimes I will also loosen the luff up some if I am trying to carry the spin higher. It's just nice to have a reference point.

thanks for the explanation.

Makes sense if you are a racer or really want to maximize every adjustment - i have never thought about my mast rake after i step my mast.. i guess it makes a small difference but isn't that controlled with your backstay (main)

QuoteSometimes I will also loosen the luff up some if I am trying to carry the spin higher. It's just nice to have a reference point

- ohhh yea, i forgot that if you are in a position where you have to sail higher, you can losen the head and tack ....

Why do you need a mark? couldn't you just hoist till ya hit top and then back off an inch or 2?
bacho

Rank: Mate

Registered: Jun 17, 2011

Last visit: Sep 24, 2023

Posts: 783
Posted: Aug 08, 2014 - 09:57 AM

On a given day racing, I might adjust the tension a couple times if it doesn't feel right. Once I feel I have found a good spot, I can replicate that exact adjustment every time I round the A mark.

The C2 is more sensitive to the fine adjustments than all of my previous boats, but once you get it right, it absolutely flies downhill.

--
Greenville SC

Offering sails and other go fast parts for A-class catamarans
--
Edchris177

Rank: Chief

Registered: Nov 26, 2009

Last visit: Aug 10, 2024

Posts: 2531
Posted: Aug 09, 2014 - 07:07 PM

QuoteI just noticed that your spin bridals don't go to your bow tips. this is the first time i have ever seen a boat like that. Please verify this is correct

Correct. They go from pole end to a fitting on the front spreader bar, which is basically where the regular bridals attach to the hull.
On the 10' beam boats, the front spreader bar,(a 2" pole that also serves as front bar for the front tramp) is required. It has a fitting at each end for the spi bridals, that is the standard factory setup. I have seen where people have drilled holes at the bow, & some modern boats have them, but I have not seen that on the Mystere 6X's
The bows make more sense, the angle is more favourable than going back to the bridals.
Two other questions;
1) What do you do with the lazy sheet on the spin?
In photo 1 you can see it is well up on the jib. This happens if I don't get enough slack while gybing. It usually rides down on the furler drum. Do people use an kind of fairlead, or loop of line to control where it lies?
2) Unrelated tot he spin, but what is the clamcleat used for that is on the bottom of the boom, right under the rotator clamcleat?
I have seen it on several Mysteres...

QuoteAlso let the mast rotate all the way out, if you have a positive rotator, use it to point the rotator bar straight down the beam.

Forgot about that, tried it today, was surprised at the speed I had from 6kts wind. Flew the kite 7 miles home...after I sorted out the mess from shrimping it, due to not making sure the halyard was clear before I started the hoist, man I gotta find crew for this beast!
One last question, what diameter line are you guys using?
I have 1/4", it gets kind of hard to hold onto after while, I ended up using the cleat behind the ratchet block to give my hand a rest.

Edited by Edchris177 on Aug 09, 2014 - 07:21 PM.

--
Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
--