the leech is your backstay - give your mast the support it deserves downwind

[Kay VanValkenburgh]

this photo stood out in a slew of post-regatta beauty shots, and seemed worth putting on the forum.

note the bend in the mast. there is no tension on the leech (the top 3 battens are blowing forward).

no masts were harmed in the making of this photo, but I'd hate to see my stick in this position. when I drive down wind, I always trim on the main until its leech telltales are just breaking: I'm convinced it's faster (verge of a luff and all that) and I believe it will always keep the tip of the mast nicely pulled aft (aft = away from the brink of disaster).

we've all been out in nuking conditions (40+ kt puffs). my first time with the carbon stick in 40+ was while sailing Paul Young of Rondar. his very strong recommendation was to keep the main a bit tighter in those conditions. seems sensible to me. I've focused on trimming the main a little tighter in puffs rather than easing (my old habit). I seem to get plenty of acceleration from the spinnaker while getting a little more security for my mast.

also probably worth noting the tight lower shrouds in the photo. there has been a lot of discussion around how to adjust the lowers. Paul's strong recommendation is to keep them very loose in big breeze. if I understand correctly, his reasoning is that loose lowers let the mast move forward at the spreaders. If you hold the spreaders back and the mast tip blows forward (as in the photo), voila, you have an inverted mast.

Interested in others' thoughts.

[Jeff Jones]

Kay, thank you for the post.

It appears they have the boom quite aft of the shrouds but the GNAV is off.    I thought i read somewhere that you should keep the boom at least 18" from the shrouds with GNAV on in a breeze.

Is this your experience and how do you see the GNAV playing into the equation?

[Drew Harper]

That looks horrible...I have a worse one to look at though. This shot is of a U20 just before the rig timbered. They hit a puff, eased the vang and 200 yards past this point....BOINK. Look at how far out they have eased the main....yikes....and that funny little bend just above the gooseneck.

Two things happen when you overease and/or undervang. The rearward force is reduced but ALSO, and perhaps even more important, the sail levers against the spreaders, twisting the mast. Masts only like forces in a couple of directions...you add twist to compression, shear and tension, well, I don't think it's a good thing :-))

My take (read, probably wrong...LOL) You have 4 things keeping reward pull on the mast. Main sheet and vang provide leech tension. Cunningham keeps the luff pulling down on the masthead and cap shrouds keep significant reward force on the stick.

I think most of the carbon sticks have failed in sudden conditions...that is to say, they were tuned for 10 knots and 30 knots came down the racecourse.

I sail in decent breeze most of the time and keep loads of cap shroud tension. I used to keep a very loose set of lowers, but the big problem there is if it starts to nuke, you can't control your headstay enough....hence the whole Alcatraz fiasco. Minimal blocking, very loose lowers and a 30 knot puff...we couldn't ease the headsail enough to avoid a knockdown. My philosophy now is solid mast blocking and not quite as floppy lowers...though still pretty loose.

I tie a knot to prevent the boom from getting closer than 16" to the lower shrouds. I always keep hard vang on....even when we're crashing. I find the rudder is so dinky that no matter what, when it's crashing, it crashes. Careful, if you find yourself off the boat, the knot is NOT your friend....see shot below of my boat sailing away on a screaming reach, solo (well, except for those f'n trained gerbils driving it)

We have the kite halyard ease thing down to an artform when we broach...it just works easier for us in big breeze. We ease off 8' and the boat is immediately righting, helm and #2 move to the rear corner...a three count and on 3, helm and 2 hit the rail hard, #3 comes up to us  pulling the kite halyard...when it's topped, he calls out then 2 trims the kite as the boat is rolling to weather and it freakin' explodes onto a plane....fun but a little weird the first time.

I'm very interested in hearing about other strategies on broaching and keeping the boat under the rig in the breeze.

[Justin Scott]

I love huge breeze down wind.

Checklist:-

Vang on.
Its faster and keeps the mast in column.

Main sheet relatively close in (there's lots of apparent wind) and in a puff, bear away and sheet in more!

As you approach the windward mark, whale on the cunningham. It twists off the top of the main and stiffens the rig like the string of a bow.
Remember to ease a bit at the leeward marj before you go upwind or you will have a little "airbrake" action going on at the top half of your rig.

If you crash and burn down wind, (which is lots of fun in itself) and you ease the vang to stand up, remember to get it back on quickly. The rig is most at risk when your are going slowly accelerating in a puff with lots of water sluicing around.
When our vang is eased or manisheet out (eg for emergency bear away) we call it "Rice Krispies" mode. The U20 in Drews photo was defintely in Rice Krispies mode.......Snap, Crackle Pop! We dont like to be in Rice Krispies mode. A Viper carbon rig is much more tolerant than aluminum rigs of U20 etc., but be kind to your rig.   

[Dan Tucker]

this photo stood out in a slew of post-regatta beauty shots, and seemed worth putting on the forum.

note the bend in the mast. there is no tension on the leech (the top 3 battens are blowing forward).

no masts were harmed in the making of this photo, but I'd hate to see my stick in this position. when I drive down wind, I always trim on the main until its leech telltales are just breaking: I'm convinced it's faster (verge of a luff and all that) and I believe it will always keep the tip of the mast nicely pulled aft (aft = away from the brink of disaster).

we've all been out in nuking conditions (40+ kt puffs). my first time with the carbon stick in 40+ was while sailing Paul Young of Rondar. his very strong recommendation was to keep the main a bit tighter in those conditions. seems sensible to me. I've focused on trimming the main a little tighter in puffs rather than easing (my old habit). I seem to get plenty of acceleration from the spinnaker while getting a little more security for my mast.

also probably worth noting the tight lower shrouds in the photo. there has been a lot of discussion around how to adjust the lowers. Paul's strong recommendation is to keep them very loose in big breeze. if I understand correctly, his reasoning is that loose lowers let the mast move forward at the spreaders. If you hold the spreaders back and the mast tip blows forward (as in the photo), voila, you have an inverted mast.

Interested in others' thoughts.

Yes, that's a scary looking mast. Stuff the boat into a wave while in a  decent puff (or just a nuclear puff) and you could be picking carbon bits out of your hair. Beautiful photo though, with the sun on the red kite! Ultra nailed it, the GNAV is off, so no leech tension, even though the boom angle is okay.

Good observations and advice. I was asking Paul his opinion on where I should have the lowers on Day 2 of the NA's. His quite serious response was, "In the boot of the car if it were up to me". His philosophy is very KISS - no blocking ("throw them overboard") to allow the full length of the mast to bend and depower the main, very loose lowers (touch the uppers 4' from the deck). Ease the jib not the main upwind in the puffs, so you keep the forestay tension on with the main leech. He insists you don't need to play a lot with upper (Cap) shroud tension, but I have not found that the be the case.

Downwind, his rule is small ease on the GNAV, don't really open up the leech (i.e. keep the battens parallel to the boom), don't ease the main past the spin turning blocks. I have my mainsheet marked at the max ease position, but have more to give. I'm a bit skeered of Drew's knot a max ease...


This tuning philosophy has worked well for me with the Hyde MI and MkIII sails. We've had the boatspeed to hang with or occasionally even roll uber-tweakie sailmakers, when the knob at the end of the tiller is working well. That being said, I'm now prepared to start finessing a bit more with blocking and fine tuning lowers and see how that goes, trying to eke out a fraction more speed

[Dave Nickerson]

Drew ? Nice downwind recovery tutorial for breeze.  Makes me want to dump the boat just to give it a try.  Actually sounds like fun!  Still learning the nuances of getting these boats down the course quickly, so nice to see other inputs. 

Upwind, I think upper and lower shroud tension and mast blocking are bit a function of whose sails you are using and how much luff curve (or luff round) has been designed into the front of the sails.  My impression is that the new Hydes, Norths, Doyles and UKs are converging a bit in this area, compared to the older Hydes which are pretty deep.  Haven?t seen enough of the Q mains to have an opinion - am guessing they are similar to the other new generation sails.  In general, we?ve had pretty good height going upwind (UK Dacron main & Pentex jib), though are still working on being able to consistently replicate our fast forward gear ? that seems to be a time in the boat thing.

In breeze we generally trim the main pretty hard and aggressively ease and re-trim the jib to help maintain a relatively constant angle of heel.  Vang gets adjusted a lot to add/lose power based on the puffs (a car and track on the boom and a 16:1 purchase is a wonderful thing!).  Always frustrates me though when you do need to ease the main and the headstay sags and the jib then gets more powered up ? exactly when you don?t need it.  So, in full hiking conditions, we?ve been using mast blocks and rig tension to help control that sag. We?re using blocks that keep the mast at the same place in the partners as with about 28 on the Loos gauge. 

Upper shroud tension is a function of windspeed and sea state ? how much power do you need?  Might start out in 8-10 kts with the uppers at 28 (Loos).  By the last race on Saturday at the HPDO when it was nuking, we were up to 38.  These numbers will likely vary a bit based again on whose sails you have and how deep they are. 

We?ve then been adjusting the lowers simply to where the mast is straight when sailing up wind ? helps maintain forestay tension and is easy to judge (just sit on the foredeck facing aft and sight up the front of the mast).   

On our shrouds, two turns of the uppers seems to about equal one number on the Loos gauge.  Half a turn on the lowers for every one turn on the uppers tends to keep the mast pretty straight.  Makes it easy to replicate settings ? if you can keep track of the turns (we?ve started to write them down on the deck)!  It's all actually pretty simple.

[Paul Young]

Don't normally get involved in forums but .... here goes.

There are two seperate issues in this thread. The first brought up by Kay, is that the boat in the photo is inverting his mast. Everything said so far is correct, in that he needs more upper shrouds, less lower shrouds, more gnav and less mainsheet. All of those things keep the mast bent the right way, and are faster downwind, becuase you have a flatter, lower drag sail, more power, more speed, and therefore less load on everything becuase you are moving faster reletive to the windspeed.

The second issue is how it is best to go upwind in breeze. The important thing here is keeping the slot open, so the air has somewhere to go. There are two ways of widening the slot. One is to tighten the uppers, loosen the lowers, and allow the mast to bend forwards and up to windward in the puffs ( this cannot happen with tight lowers). This flattens the front of the ,mainsail and opens the gap between back of mainsail and jib.

The other is to really play the jib in the puffs. As the mast bends up to windwards in the puffs, you get luff sag on the jib. This makes the jib fuller, which is good, and makes it easier to steer, and at the same time it gives you more leech return which is bad, because it directs the air into the back of the mainsail. Playing the sheet,and easing the leech in the puffs, controls the fullness of the jib, and keeps the slot between main and jib open. It also gets rid of the lee helm that happens when the main is eased in the puffs and the jib is not.

If you have sails that are too flat, there is not enough control of the Viper rig to really make them fast across the board. You need a certain amount of depth, to allow the mast to do its job, without destroying the sail shape. Fuller sails are easy to flatten, by winding on the cap shrouds, and much easier to power up but it is much harder to keep the rig straight enough for flat sails across the wind range. So, as Dave says, the rig tune you need is going to be based upon the sails you have.

Paul.

[Jay Harrell]

note the bend in the mast. there is no tension on the leech (the top 3 battens are blowing forward).

I got curious whether that mast was actually inverted, or it was mostly an illusion created by the inverted batten.  So I drew a straight line up the mast, and here's the result.  Notice that the mast follows the green line - it's the sail that's sticking out the back.  So despite having the wrong and dangerous sail trim as described by all, the mast in this photo is still holding up just fine.  Now, if the wind came up a bit, it might be a different story.

[Dave Nickerson]

Paul - thanks for clearly describing the "no mast blocks - loose lowers" tuning alternative.  Now that I actually understand it, time to give it a try.  I assume you have the lowers tight enough that the mast is not sagging to leeward at all.
And keep please keep sharing!

[Harvey Barnes]

... I find the rudder is so dinky that no matter what, when it's crashing, it crashes.

One thing worth noting here is that aggressive helm pumps (a la dinghy/ skiff sailing) can save a wipeout.

We all know when caught high in a big puff and a wipeout is imminent, pulling the tiller to your ear just puts the brakes on (rudder stalls) and exacerbates the problem.  Over you go.

However repeated sharp pumps (tugs to windward) followed by a centering of the helm (to re-attach flow) wiggles your ass up and your bow down.  Keep doing it until you regain control  (or you wipeout).  Like in many dinghies, it seems to work really well in the Viper.  I've managed to save numerous (but not all) wipeouts.

Use this technique after a wipeout too.  When the boat stands up, pump the helm to get the bow down quickly before things load up.  You'll avoid a second wipeout and instead you'll be blasting off again in seconds.

Harv