Cutter stay on fractional rig?

Jackdaw · Dec 5, 2014

Its a good idea, and done all the time.

On the Pogo 12.50 we charter every year in Greece, we carry a solent or storm sail in a deck bag, ready to be run up on a removable dyneema inner stay. Works great. This is not us, but same boat. You can see the stay and the sail on the foredeck.

RichH · Dec 5, 2014

If and only if, you also apply 'opposing stays' such as running backstays etc. Putting up additional stays forward ALWAYS needs to be 'balanced' by (auxiliary) stays or running backstays aft of the mast. This is especially important with 'modern' rigs that use very thin section and very 'bendy' masts that highly depend on their rigging for mast stiffness for sailing in near, full gale or higher winds/waves.

Even boats with 'telephone pole' masts, need to add runners or temporary intermediate stays if they have a sail loaded forestay (the first stay in front of the mast on which one flies a sail) flying behind a headstay (jib or genoa) in 'heavy' conditions for any length of time.
The most common sail plan for such conditions is trys'l and storm jib flown on 'the usual' stays .... just to balance the force moments involved from the sails, and no need for additional stays.

In cutter rig speak: Headstay (jib/genoa) --> forestay (staysail or storm jib/storm staysl) ---> mast ---> mainsail --> running backstays or intermediate stays ---> backstay.

With a sloop rig, a simple storm jib and 3rd reef in the main (or trys'l) is the 'usual' sail plan for long term 'stink'.

Jackdaw · Dec 5, 2014

Kings Gambit said:
OK; the removable dyneema stay is what I'd consider adding. BTW, where are those guys-- Arctic or Antarctic?

Arctic.

The two tricks of the stay, where to anchor it, and how to tighten it.

On the Pogo, the stay is anchored on the bulkhead aft of the anchor locker. Its a very hard point on this (or most) boat.

To tighten, a line from the cockpit leads to a turn just aft of the anchor locker, and tuens down where a 16:1 block pulls on a line/dogbone that attaches to the stay back up through the deck. Very clever. I have a picture somewhere.

Jackdaw · Dec 5, 2014

RichH said:
If and only if, you also apply 'opposing stays' such as running backstays etc. Putting up additional stays forward ALWAYS needs to be 'balanced' by (auxiliary) stays or running backstays aft of the mast. This is especially important with 'modern' rigs that use very thin section and very 'bendy' masts that highly depend on their rigging for mast stiffness for sailing in near, full gale or higher winds/waves.

Even boats with 'telephone pole' masts, need to add runners or temporary intermediate stays if they have a sail loaded forestay (the first stay in front of the mast on which one flies a sail) flying behind a headstay (jib or genoa) in 'heavy' conditions for any length of time.
The most common sail plan for such conditions is trys'l and storm jib flown on 'the usual' stays .... just to balance the force moments involved from the sails, and no need for additional stays.

In cutter rig speak: Headstay (jib/genoa) --> forestay (staysail or storm jib/storm staysl) ---> mast ---> mainsail --> running backstays or intermediate stays ---> backstay.

With a sloop rig, a simple storm jib and 3rd reef in the main (or trys'l) is the 'usual' sail plan for long term 'stink'.

Rich,

I mostly agree on retrofits, yes. On new designs set up for it, no.

The Pogo 12.50 does not have ANY back-stays, fixed, running, or check. But the 28 degree aft swept shrouds holding the mast in compression, and the solent stay attached at the 'second hounds' at the D2 inners, the rig is secure in any configuration.

RichH · Dec 5, 2014

this is going to be long and technical.

Sorry totally disagree, as this has really NOTHING to do with the mast, its stiffness ..... NOR in actual practice whether one has swept back spreaders, runners or intermediates. If you have more than one stay in front of the mast that carry sails the tension or sag in those stays, the elastic length under those different loads that these sails impart to the stay that its attached (or not carrying a sail) is quite complex. This 'phenomenon' of load sharing between multi-headed stays is quite well known and is probably the chief reason why multi-headed rigs cannot go upwind in comparison to a simple sloop.

In a sloop as the forestay tensions, the backstay (or the swept back cap shrouds, etc.) auto tension in direct proportion to the changing load in that forestay due to sail loads. Agree?

This doesnt happen on cutter rigs and multi-headed rigs. With a head stay / forestay (forestay - where the sail immediately in front of the mast flies) combo ... there is ALWAYS a differential (non equal) sharing of loads, in each forward wire ... a 'sharing' of the total load and usually those loads are not equally shared by those 2 stays ......& into 'whatever' there is reacting to those 'wires' aft of the mast !!!!!!
When above beam reach & with NO induced change in backstay/runner/intermediate/swept back cap tension, etc. (for the purpose of simplified explanation), when one sail is being flown and drawing and other forward stay is 'bare', the stay with the sail flying will ALWAYS 'unload' most or part of its load into the other (bare) stay (yet, total load still constant TO whats behind the mast). The stay carrying the flown sail will physically reduce its tension and correspondingly the other (bare) stay will 'tighten'. Such causes the stay flying the sail to further and significantly sag off to leeward. (Its caused by the 'side loads' onto that stay imparted from the sail into the stay (in trigonometric and static analysis of 'free bodies' this is dividing by the sine of deflection angle ... causing the side load on that stay to attempt to approach infinity in the 90° direction to the load applied - elasticity & elongation!). A1 + A2 = (constant) backstay tension.
Same happens if two head sails are being flown and one is smaller in area than the other ... the stay with the smaller sail flying will tighten and the stay with the larger area sail will loosen and the loosening then causes SAG off to the lee.
In all cases, tightening the backstay, applying runners will not change the 'proportional load sharing' of the combined TOTAL load occurring in the forward wires .... although the increased tension from aft of the mast can help to restore the stay with the greatest sag happening to be closer to 'normal' ... but at the risk of over-tensioning the rig - yield failure.

After sailing (hard sailing) such a stress complex multi-headed rig for the past ~20 years (about 40-50++K naut. miles), also multiheaded schooners, sharpies, etc. .... If one wants a stress balanced multi-headed rig to 'point well' ... one HAS to go forward and 'adjust' the tension on one or both of forward stays so that the sag is essentially equal in both flying sails OR overstress 'something' to accomplish the exact same thing.
If pointing and with a BIG topsail flying 'over' a staysail (the topsail obviously sagging off to leewards) one must loosen the damn forestay (the stay that the [fore]staysail is flying. If flying a storm jib on the headstay with a larger staysl on the forestay (under), then you have to tighten the damn forestay .... and NO change in backstay, etc. because the backstay, runners, swept caps all react in direct proportion to the additive/combined TWO (or more) forward stays.

So, if anyone is considering to ADD a forestay behind (what then becomes) the headstay, Id state with my hand on a stack of bibles that that forestay (or solent stay) should have 'some' means of on-the-fly independent tension (up or down) adjustment!!!!! The use of dyneema instead of wire and run either from the tack to a bodaceous sheave high on the mast and then down to a winch ... or the reverse ... from a bodaceous deck mounted sheave ON THE DECK and run back to winch on the mast. Aint no other way to do this and have all the tensions in those 2 or more forward wires anywhere close for proper luff shape/tension control of jib/genoas etc. on a multi-headed / multi-stayed sailing boat.
Importantly, this applies to sloops with added 'forestays' ... (sometimes erroneously called 'slutters').

The real problem with adding any forestay to a frac rig sloop is that the mast is already at about 30% LOA, meaning that youre really not going to be putting up a staysail of any reasonable large sail area AND if there isnt a means to easily disconnect that forestay there simply will not be much room for a jib/genoa to tack between those TWO forward wires. Thats one of the reasons why single masted multi-headed rigs (cutters) have their masts at 40-50% LOA - big staysls and lots of space between those two forward 'wires'.

As regards the original Post, a frac rig less than 7/8 frac. will have the combined CE (jib and main) of its sail plan quite far aft in the mainsail anyway by design ... so most of the time that youre overwhelmed and needing to go upwind in F8+, you can simply sail on with a ONLY deeply reefed main ... no need for staysail, nor storm jib, no futzing around with wire tensions while the deck is being constantly swept with solid green water. Downwind in F8+is even easier ... just a storm jib. Mast headed boats need two of 'something' up when going 'upwind'.

;-)

Jackdaw · Dec 6, 2014

RichH said:
this is going to be long and technical.

Sorry totally disagree,
;-)

Wow rich, I needed some coffee before I ingested all that!

I agree with what you are saying, so I assume that what you are disagreeing with is the the use of the term 'cutter'? I took the OP's intent to not mean he wanted to fly two headsails at the same time (cutter style), but as a staysail rig designed to fly a Solent or storm sail instead of regular headsail. I'm pretty sure that's what he meant, and on what my comments were based. If well engineered, a perfectly sound, tried and true way to go.

kentobin · Dec 6, 2014

http://www.sailmagazine.com/boatworks/convert-your-sloop-double-headsail-rig
"A Solent stay is not a cutter’s inner forestay, which is farther aft and typically requires additional support in the form of running backstays or extra swept-back shrouds. This is one of the biggest attractions of a Solent rig: no extra standing rigging required. Here’s what you need to know to install a Solent stay for hanked on sails on a typical 42 to 44-foot boat."

Rick D · Dec 6, 2014

Well, I Wonder What Rig I Have?

My 40.5 has a factory staysail and removable stay with the chainplate aft of the anchor locker about 3-4' aft of the forestay. No running backstays, but swept back spreaders. Can't say how well it works since I have never flown it. Always reef the main and then furl the jib. I suspect the staysail is designed to be flown alone with the jib furled since there are no dedicated winches for it.

RichH · Dec 6, 2014

Jackdaw said:
Wow rich, I needed some coffee before I ingested all that!

I agree with what you are saying, so I assume that what you are disagreeing with is the the use of the term 'cutter'? I took the OP's intent to not mean he wanted to fly two headsails at the same time (cutter style), but as a staysail rig designed to fly a Solent or storm sail instead of regular headsail. I'm pretty sure that's what he meant, and on what my comments were based.

My disagreement is not a difference of 'terms' but rather that the functional output and control of two or more stays in front of the mast is not as easy nor as simple as it appears. Double headed rigs, even if one of the stays is 'bare', are VERY complex with respect to the stress of the wires and the resulting adverse 'stretch/sag' of those wires .... that characteristic to sag and stretch being an adverse situation that can easily lead to a very badly set and shaped sail.

With double headed rigs the corruption of 'terminology' of what each stay is called, etc. should be ignored; rather the analysis should concentrate on that 'interplay' of stress/stretch and exactly what its doing to the sails and degraded sailing performance (as would apply to safety when sailing in the higher wind ranges). My thinking is that you really dont need to think about stay and rig tension complexity which results in god-awful sail shape, etc. when youre only trying to survive in the far upper wind and wave ranges; and, when the principle of KISS should apply.

.... and with no discussion of the poor effects aerodynamically that occur when the sail's leech in front of the mainsail can only provide a too-close-to-the-mainsail tack to clew angle .... and in sloops thats a 10-12°. Do that with a short LP staysail and that needed 10-12° angle simply closes down that 'slot open distance' or that sail in front of the mast is now has to be at much greater tack-clew angle (10-12°) from the centerline than a simple jib on a sloop rig. Aerodynamic analysis seems to suggest that any 'staysail' operating in very close proximity to a mainsail luff in actuality only becomes a functional aerodynamic forward extension of the mainsail, not the aerodynamic 'bootstrapping' advantage as when sailing with a properly spaced jib/genoa on that 10-12° tack—clew line. If such is the case, It would seem simpler and far less complex to select a ('true' w/ short LP jib) fractional rig and only have to 'play' with one sail when at the high wind ranges - only a very deep reefed mainsail. Maybe thats why most of todays designers are tending to abandon the cutter rig and the masthead rig and are concentrating more on fractional rigs (and use the correct sized spinn for sailing downwind). Perhaps too, solent rigs are intended simply for those who are afraid of using a spinn in 'high wind' conditions?
I guess what Im saying here is that if I were today building or looking for a brand new boat for far offshore / long distance work, it wouldnt be a cutter rig or mast head rig but a simple ~3/4 fractional sloop with LARGE main with BIG roach, and a short LP jib ... and simply enjoy myself 'tacking downwind' and for a hell lot less 'work'. ;-)

Jackdaw · Dec 6, 2014

Kings Gambit said:
Yeah--what I got from Rich's explanation is that the forestay of a double-headed rig will transfer part of its load under sail to the headstay, causing it to tighten up, which in turn allows the forestay to sag away to leeward. I'm not clear on why this happens but one cannot effectively retension the saging forestay using the backstays because the headstay is still loaded as well. The only (good) way then to tension the forestay itself is directly, by tugging on it where it's tacked to the deck. I think that is what the Sail article shows. All of that being said, my perceived need for a forestay (Solent) would be to rig the boat for F 7 - 8 conditions with storm jib, and still make progress to weather, or hold the boat to weather, etc., not to redesign the boat into a functional cutter rig.

I can tell you from personal experience that a well-founded solent setup is a dream. As Rich mentions the key is getting enough tension on the stay to prevent sag that will drastically overpower the sail. On the pogo, the Dyneema DUX (pre-stretched) stay is tensioned with a 12:1 block system lead aft to a 42:1 power ratio winch. Do the math to figure how much a man could load that system up. You could break the boat. It then locks at the deck with a remote halyard lock to keep any (slight) stretching of the tension system out of the stay. In 30+ sustained knots we simply powered upwind under reefed main and solent like a witch.

Jackdaw · Dec 6, 2014

RichH said:
My disagreement is not a difference of 'terms' but rather that the functional output and control of two or more stays in front of the mast is not as easy nor as simple as it appears. Double headed rigs, even if one of the stays is 'bare', are VERY complex with respect to the stress of the wires and the resulting adverse 'stretch/sag' of those wires .... that characteristic to sag and stretch being an adverse situation that can easily lead to a very badly set and shaped sail.

We are in violent agreement!

RichH · Dec 6, 2014

Interesting. Ive never found a solent rig to have 'good' pointing ability .... unless one unloads one the 'inactive' solent stay or grossly over-tensions the backstay or applies bodacious running backstay tension. The worst one I ever sailed had triangular plates at the head and tack with the two solent stays attached to the triangles ... and only one connection from that 'triangle' to the mast head and the 'bottom' triangle to the tack connected to the stem. It was like sailing a boat with 'rubber bands' for its 'forestays'.

topcat0399 · Dec 6, 2014

This is a very interesting subject.

In our first years with our fractional rig boat I adhered to what I thought was the conventional wisdom gleaned from here and other places on the internet that I would'nt be able to go up wind when it was blowing hard without the head sail up.

This year we have discovered that this just isn't totally true. The wind gets way up and the boat get seriously squirrely. Dropping the head sail the boat settles quite a bit and we can still get around pretty well under just main sail.

Sometime I would like to try it on a mast head rig.

RichH · Dec 6, 2014

Topcat ... next time increase your main halyard tension a LOT and (if you have one) apply strong cunningham tension. That will shift forward the point at which the maximum draft occurs in the sail (the draft will move 'forward') and most times will allow you to sail on effortlessly and without much increase of 'weather helm' because of sailing without a jib. This is only for fractional rigs, doesnt work well for masthead boats.

Kestle · Dec 6, 2014

I added on of these to our boat, and I read a lot prior to doing so...and am glad I did.

Many of the articles, such as this one, went into running rigging and sail points, but left out the loads (and their distributions) of the padeyes for the tacks. These need to be reinforced to the hull and not just attached to the deck. Our approach was to mount them as if they were the only forestay. Our halyard block attachment points are just below he forestays.

We took a different approach to the inner stay issue. As I solo a lot, I went with a wire within the storm sail. While trim is not as good as a hank on, I also don't head as high in big wind to reduce fatigue.

As the prior point was made too, the load balance is complex. We found we could ease off the backstay to adjust the other forestay tension as needed.

Like many things in life, YMMV. This works well for us.

Jeff