Solent Stay Question

[jjt]

As I see it there are 2 possible solutions:

If the distance between the forestay and the solent stay is big (a slooter rig), the foresail should be a 110% high clew yankee, in this case I think you even need to furl partially the sail to tack.

If the distance beetween both stays is very small (a real solent rig), the obvious solution is to rig the bigger sail in the solent stay and to rig the storm sails in the forestay so you can tack your big Genoa as any other sloop and you only need to furl a much smaller sail to tack (very seldom but in high winds)

[estarzinger]

Originally Posted by TassieBloke

I would like to modify it to a Cutter Rig, mounting it as an inner forestay and using the furler, but (and here is the BUT), I would like it to be removable (to free up the deck area when at home on the hook), and be able to remount it back to being a Solent Rig

well the obvious way to be able to do all that is to use a removable 'code zero' style furler (perhaps a facnor or Karver). That gives you a furling sail and stay that you can completely put away when you want.

I happen to have just delivered a boat with a #4 heavy weather jib set on a solent stay with a karver furler exactly as you would like. These can work really well but there are some tricks.

1. The furler worked well, except the furling line had been cut too short and we could not get it on a winch. It was easy to furl in 20 kts but the sail was designed to use in +30kts and it was not so easy to start the furling by hand in that wind - really needed a winch to get the furling started.
2. There was a 2:1 low stretch halyard and that is necessary to get good/proper stay tension for upwind sailing (otherwise the luff will sag off). Many of the French boats use a 3:1 tackle on the tack (winched thru a spinlock ZS jammer) to get even more tension, but the 2:1 seems to work ok and is easier/cheaper to set-up.
3. This particular sail had some sort of funny vibration in its upper quarter and did not appear to have been properly cut for the rope luff application. You really want a sail maker that has done these before for a top boat (open 60 or volvo or equiv) to be sure they know how to do it. If you plan to leave it set in place for any lengths of time, then you do need some sort of leach UV protection (which the racers do not use).
4. All the hardware is pricey and can add up to a big bill, but the end result is quite impressive and flexible and easy to use.

If all that is too complex or expensive, honestly a dyneema stay with hank on sails is pretty bulletproof and not to difficult to work. Before you go offshore you set the stay and hank on the sail. You do have to go to the mast to hoist it, but really that is not so troublesome.

[RichH]

Downwind sailing with a solent stay isnt going to be a problem; however, without other radical changes the boat will now, when going upwind, point like a PIG.

Adding a 'solent stay' will adversely affect the upwind performance of any boat. There are significant structural issues also ... with respect to the BACKSTAY system. Add a solent stay and the boat will 'point' like a pig, will begin to aggressively heel over when attempting to point, and you can also develop more 'skid to leeward' when pointing. Pointing ability is affected by how close the headstay or forestay or solent stay is operating to the boats centerline.

Most sails are target designed to be flown in 15kts of windstrength with the stay that they are applied operating at 15-20% static (dockside) tension in the wire. This 15% static tension will, when the sail is fully windloaded to max. (15kts / beating), cause a very predictable sag in the wire. To compensate for this predictable sag the sailmaker will slash away a portion of the luff to *compensate* for the expected sag of the wire - this is called 'luff hollow'.

The problem with solent stays on sloops or 'forestays' on cutter rigs is that two 'forward' stays are reacting with only ONE backstay. If the backstay is operating at 15% then each (unloaded) forward stay will 'divide' the force and each will be operating at ~7.5% in total reaction (7.5 + 7.5% = 15% to react with the backstay.

Not a problem you say, just apply double the tension (30%) to the backstay. If you said that, go to back of the class as you are 'crossing' some very important structural/metalurgical properties of 300 series stainless - the most common materials used in rigging: fatigue endurance limit of the material. The commonly accepted *fatigue endurance limit* of 3000 series stainless is 30,000 psi. Loads, especiallly 'cyclical' loads, over 30,000 psi cause the material to rapidly fatigue/fail. The 'rule of thumb' is 1 million load cycles above 30,000 psi will cause the material to catastrophically fail by embrittlement or fatigue failure. Keep those loads UNDER 30,000 psi and the fatigue will be minimal and you can get the number of applied loads approaching 'infinity'. So loading up the backstay tension to solve the 'unloading' of EACH forward stay to configure/adjust the correct windloaded SAG in the wire is going to cause the rig to have premature FAILURE. The problem with flying a headsail on a wire that is tensioned LESS than 15% is that the (elastic) wire will now be operating at midpoint of span .. *WELL* off to leeward ...about 18'' off of center on the typical 65ft. mast hgt. instead of the normal approx. 7-8'' 'off-center'. This leeward and rearward SAG of the head/forestay when 'pointing' will cause the boat to aggressively heel over, the position of max. draft in the sail will move radically 'aft', the leech section will be 'hooked up' to weather, the amount of draft will increase ..... the result: a boat that become increasingly tender, heels over aggressively, cant point worth a damn, skids off to leeward, and is SLOW.

Add a 'heavier' backstay? ... still a problem as youve now added axial compression to the mast which influences the possibility of 'buckling failure', etc.

Recut the luff hollow section of the luff, recutting so that the new luff shape matches the wire at 7.5% tension? Will work for upwind sailing; but now when going 'downwind' the headsails sail(s) will be 'draft forward', flatter, and the leeches will be 'more open' - the exact opposite of what you want in a downwind sail shape configuration.


So if you want to add a 'solent stay' (or add a forestay to the existing headstay of a cutter rigged boat) you really should have at least one of the forward stays so arranged that you can 'adjust' the amount of tension it receives ... and then go forward and 'readjust' every time you NEED to go onto a beat !!!!!!!

The reason that cutters are such poor performers when beating is this 'interplay' of variable sail loading causing 'variable' headstay/forestay tensions !!!!!!! A tight forestay (the stay just in front of the mast) will cause the headstay to unload which causes the headsail to operate waaaaaay off to leeward, etc. when beating. If you want a cutter to perform well when beating ---- you HAVE to manually unload the forestay so that 'most' of the tension 'transfers' to the headstay !!!!!!!! ... same thing with a solent stay arrangement. For a solent stay rig, to make it 'Point' you must be able to 'unload' the 'unused' stay. You can do this by terminating the 'tack' portion of the wire to ultra high tech line (dyneema) running to a reinforced deck mounted block then back to a 'winch' or 'magic block', etc. so that you can 'vary' the loading to affect the 'proper' sag in the wire (but that loading shouldnt go much 'above' causing any the rig wire to go 'over' that 30,000 psi fatigue endurance limit ... or you risk premature rig failure.

With 2 forward stays when you add winch pressure to the sail loaded stay, the tension will 'equilibrate' to the other stay that isnt 'windloaded' .... and excessive winch pressure on the 'jib sheet' becomes an *additional* problem on the now 'loosened' windloaded stay ... causing even more draft aft, increased draft and leech hooked to weather shape.

(FWIW - all my jibs and headsails have 'luff stripes' applied so that I can 'eyeball' the amount of SAG in the luff shape that is occurring and so that I can make the proper rig tension adjustements ... so that I can make my cutter point. This is just a straight as an arrow 'run' of stitching that is applied to the sail... aboout 12'' back from the luff and runs from near the tack all the way to the head. When I NEED to 'point', I just walk forward, eyeball to see if the 'luff stripe' is straight when viewed at 90° from the centerline and then make any adjustment (but not going above 30% rig tension) to get that 'luff shape' correct. I can outpoint most cruising type 'sloops' with a crab-crushing 'cutter'. Adding 2 forward stays adds a great amount of (unneeded????) 'complexity' and structural requirement considerations. A sloop is a uniquely simple rig ... and all the 'wire tensions' are easy to ascertain especially to affect GOOD sail SHAPE; a solent rig (or a 'cutter rig') becomes a VERY VERY complex situation especially when there are TWO headsails flying and the windloading and Sail Areas are different and you WANT to preserve that necessary (already designed-in) luff (hollow) shape.


Ignoring the above discussion If I were to add a solent stay to a sloop I'd add the solent in front of the existing forestay, make it tension adjustable so I can control the LUFF shape and position, and thats where Id load the 'light weight' lighther wind jib. This would allow one to keep 'normal' jib free for tacking 'through' the foretriangle .... the 'light sail' would have to be tacked through 270° in 'light winds' ... and besides in 'light wind sailing' rig tension isnt as important as when at 15kts and above. With a solent stay rig, you will also need to add running backstays ... to secondarily 'help' with tensioning the 'forestays'.


Thats my story and Im sticking to it: Solent rigs and Cutter rigs are a ROYAL PITA to sail .... if you want to 'point'. Hope this helps. :-)

So, if you want to make the boat point like a PIG, add a 'solent stay' and provide NO means to (constantly and independently) adjust at least one of those forward stays. FWIW ... if you want your rig to last, dont exceed 30% backstay tension for long periods of sailing time.

Sorry for all the run-on sentences but Im using Firefox and when uploading to this particular website all the paragraph marks are always 'erased' - sorry.

[RichH]

BTW - thats 300 series stainless not 3000 series .... for some reason I cant edit my own posts here, etc. and that why I usually avoid this website.

FWIW- ... and this is the 'heart of the problem' with having two or more stays with loaded sails in front of the mast ......

Here's an article I wrote some time ago with respect to rig (forestay, etc.) tension vs. 'luff hollow':
http://www.cruisersforum.com/attachm...3ebb36bdd5.gif

[estarzinger]

Originally Posted by RichH

Downwind sailing with a solent stay isnt going to be a problem; however, without other radical changes the boat will now, when going upwind, point like a PIG.

. . . .

Just fyi . . . the code zero approach to solents pretty much solves all this problem, since the solent 'stay tension' is easily adjusted by a 2:1 (or 3:1) halyard. You can obviously do this adjustment at the mast or cockpit, whereever the halyard is led. Many of he French offshore race boats use this approach and they point decently - as well as any racer will want to offshore (which is a bit lower than a flat water w/l racer would want).

And usually a hank-on solent stay has a pelican hook adjustor (like the nice wichard ratching unit) at the bottom, which also makes the stay tension pretty easy to adjust, but you do have to go to the bow to make the adjustment.

[Cheechako]

The Solent is trying to bend the mast with the top considered the "fixed end". My guess is a couple of feet is not an issue for sure.... think about a 2 ft long chunk of mast section... how hard do you think it would be to bend that? A boom is unsupported for it's length on many boats....
I think most people intend to use the Solent stay for a jib, not to use in conjunction with a genoa also. Great discussion above, but I'm having trouble understanding why flying a jib to weather with the top end slightly below the Forestay would go to weather like a "pig". My buddy put a solent on his Gulfstar 44 for this reason, heavy wind sailing. They sailed to New Zealand and loved the system.
I think it's a matter of how you use it. I found nothing like a PITA with my 3 cutters 38-47 ft. In fact, in a real blow, there's nothing like sailing fairly flat with just the stays'l and reefed main at 7.5 knots! The boat really cut through waves to weather that way.

[delmarrey]

Originally Posted by RichH

ummm.... thats 300 series stainless, not 3000 series - sorry but Im unable to make 'edits' for some reason. (Thats why I avoid this website).

Actually, that is 300 series.

You make some good points. Although, not all would be using both forestays simultaneously. In my case I'll use a solent for a heavy weather sail and save the big genoa for lighter air (up to 25 kts reefed).

The advantage being one can pull the solent stay back out of the way when the genoa is being used. And the main purpose is to keep the COE around the mast by reefing the main as far down as needed and using the solent up to being the last sail up in a blow.

As for back stay tension, I would imagine that would depend on the boat. In my case the rig is over sized with a hyd. back stay, that I keep at around 1200 psi but can and have pumped up to 5000 psi for flattening the main. But those were the racing features, which I hardly ever use.

Having to re-tension forestays with both in use makes perfect since. If one wanted to really run a cutter rig continually then I would think a 60 -70% fractional second stay w/running back stays would be a better set up, considering the boat.

[hellosailor]

Tassie-
I'd expect that what you want to do is perfectly feasible, the only real question is what bits of hardware you'll need and who offers them. If you call someone who makes the fittings (in the US I'd say Harken or Garhauer) to see what they offer that may solve the puzzle. Since you've either got a lot of math or some hands-on experimenting to get balance right, I'd suggest a robust low-profile track running fore/aft on the deck rather than trying to get a single attachment point in the right place. Then you can just fit whatever you want to try, and change it as need be.

[RichH]

Originally Posted by Cheechako

. Great discussion above, but I'm having trouble understanding why flying a jib to weather with the top end slightly below the Forestay would go to weather like a "pig". My buddy put a solent on his Gulfstar 44 for this reason, heavy wind sailing. They sailed to New Zealand and loved the system.

Its not the the top of mast that is flexing between the head and the hounds that is of concern ; but rather, if 2 stays in front of the mast are connected, between 'somewhere' near the top of the mast and at the stem of the boat, the one that is (visibly) 'bearing more the load' of the sail will automatically 'unload' into the 'lazy' stay .... the stay with the sail flying will relax and the 'lazy' stay will tighten. The now less-loaded stay flying the sail will cause the luff shape of 'sail' to become grossly distorted.
This is all a function of the elasticity/strain of the wire and the 'average' reaction to a backstay system (or runners) .... and can easily be calculated via 'statics analysis' and simple trigonometry; or, simply watching the luff sag off to leeward and to aft which adversely affects pointing ability.

;-)

[Jim Cate]

G'Day RichH,

Thanks for an interesting discussion of the Solent rig.

I have certainly noticed the problem of maintaining tension in ours, which is organized a bit differently than the masthead situation you describe.

Our rig is fractional (about 5/6) with well swept back spreaders and dyneema runners. The backstay to the masthead is quite light and used to bend the top panel of the mast.

Our 120% Genoa on the outer stay was successfully compensated for sag in its design stage, but the inner sail (essentially a #4 jib of ~90% and full hoist) was not. Its shape deteriorates rapidly as the wind increases, and I've been contemplating trying to increase luff hollow to reduce this effect.
I'm not too worried about this sail being too flat off the wind -- we've other ways of powering up under those conditions.

Now I'm considering your concerns about rig loads. Analysis of stresses in our sweptback spreader rig are beyond me, and I wonder if you have any comments along those lines?

Cheers,

JIm

[RichH]

If you have basic trigonometry background, the resultant force calculations are quite easy if you calculate everything (each shroud) into x, y, and z directions .... consider each of 'segments' (individual shroud you're analyzing) as a individual parts of the whole.
An elemental text on mechanical/structural/civil engineering 'statics' analysis would be quite easy to follow, ... if you have the 'plane trigonometry' background.

[Eleven]

First use the main sheet and backhaul? (keeps the tail of the boom up) to keep tension in the forestay system.
Second, make the solent stay a quick remove job with a shackle at the foot, and the spinnaker haul as it's hoist and tension. It shouldn't be necessary to go forward of the mast.
Three, for storm sailing shape isn't critical unless you are forcing into the wind, consider a similar storm main, a tiny sail, to keep the aero balance with low CofE if you have to go hard into the wind.
Four - storm sails get so little use that they are an excellent investment lasting the life of the boat with just a little housekeeping after use.
Five - I'm considering a jib pull down line as mentioned on another thread (single handing) to avoid putting my considerable weight on the tender bow of my little boat and myself to far from the controls. If the pull down is threaded through all the hank on's then I'm hoping I won't have to furl the sail until I'm tied up snugly in flat water.
Six - I'm quite happy to sacrifice 'good' sailing for safety.

[Weyalan]

I am also kicking around the idea of fitting a (detachable) solent stay for hoisting a small jib aft of the main (furling genoa). I'm not too worried about balancing the tension between the forestay and the solent because I only intend to fly one or the other... i.e. fulring genoa to, say 25, then roll that up and pull the solent stay forweard fromt he mast and connect it and hoist a #4 jib, to, say, 40, then drop that and pullup a hank on storn jib. So the genoa and jib will not be flown simultaneously.

My questions though, are as follows:

1. Attachment at the mast. I plan to attach the stay approx 300-400mm (12-16") below the forestay. I have had it suggested that a standard T-ball fitting (as used for the shrouds) will be fine for the attachment. The alternative would be a tang on a collar that rivets onto the mast. In some ways the T-ball fitting is more "elegant", but given that the solent stay will be used in high wind, hence high load conditions, would this be strong enough, or would the riveted collar be better?

2. Attachment on the deck
There is a buckhead about 1.2m (4') back from the stem. I was planning to put the bottom hard point for the solent stay directly over this. The bulkhead is about 10mm (3/8") ply, glassed onto the underside of the deck and inside of the hull. It has a fairly cut-out in it to allow acces forward, so there is probably only about 150mm (6") of bulkhead above around the deck and hull sides.... i.e. it is more like a substantial ring-frame than a bulkhead. So, the question is, would this be likely to be strong enough for the loads associated with the solent stay attacment (via backing plates), or will I need to fashion some sort of tesioning strop down to the hull?

[delmarrey]

I did a test run attaching a small jig between my spinnaker boom cunningham and a padeye just forward of the forward hatch. Then took it out in a 20 kt breeze.
The padeye had no under deck support but it seem to be OK. The real problem was the cunningham was pumping the mast really bad so I pulled it down after a short time. Obviously, the mast would need running back stays to support a center mast attachment.
So, I'm going with the solent rig. But I'm still installing a bulkhead under the padeye w/a thru/chain plate. I need to build in a bathroom in this old racer anyway.

[estarzinger]

Originally Posted by Weyalan

1. Attachment at the mast. I plan to attach the stay approx 300-400mm (12-16") below the forestay. I have had it suggested that a standard T-ball fitting (as used for the shrouds) will be fine for the attachment. The alternative would be a tang on a collar that rivets onto the mast. In some ways the T-ball fitting is more "elegant", but given that the solent stay will be used in high wind, hence high load conditions, would this be strong enough, or would the riveted collar be better?

T ball is perfectly ok if properly installed.

2. Attachment on the deck
There is a buckhead about 1.2m (4') back from the stem. I was planning to put the bottom hard point for the solent stay directly over this. The bulkhead is about 10mm (3/8") ply, glassed onto the underside of the deck and inside of the hull. It has a fairly cut-out in it to allow acces forward, so there is probably only about 150mm (6") of bulkhead above around the deck and hull sides.... i.e. it is more like a substantial ring-frame than a bulkhead. So, the question is, would this be likely to be strong enough for the loads associated with the solent stay attacment (via backing plates), or will I need to fashion some sort of tesioning strop down to the hull?

Harder to answer. The ring frame sounds sort of ok, but 6" x 3/8" ply is not exactly a massive support. it certaintly would not hurt to run a strop from the deck to the hull bottom. You could perhaps try it without the strop and see if the deck lifts at all.

......