Removeable Inner Forestay- High Modulus Line vs Wire

[estarzinger]

Originally Posted by SV Escape Plan

Yes provided you have a decent halyard winch and the sail you are using has a good quality luff rope/wire. Remember the luff of the sail will be under the same tension as the stay. I have done this on several boats with good results. It also allows you room to adjust tack height and therefore sheeting angle.

hmmm . . . I have played with this on a couple boats. I have found two things.

#1 works best with a 2:1 halyard - better stay tension. Just for instance - I need about 3000lbs of tension on my stay to get it straight enough for decent windward performance in a gale. My winch halyard is a 46. I can get about 50lbs on it (taking into account the friction in the system) - so only 2300lbs. But with a 2:1 I can get above the required 3000lbs. I will note that the racers I have seen who use tackles all use 3:1 purchases.

#2 You need to be careful about the engineering of the halyard sheave in the mast - they were typically NOT engineered to take the stay loads - which are typically higher than the halyard loads because of masthead whip. In the worst case you can pull the sheave out of the mast if trying to punch to windward in a gale with bad waves.

[silverp40]

Mark Johnson, your 3rd picture shows a staysail stay storage method that looks neat - where did you purchase the white soft stay "holders"?

Also, would you happen to have another picture of the base of the stayail stay in the stored position?

Sorry for diverting a bit off topic....

[ThereBePirates]

The sails are cut for your forestay, I had the problem that when attaching them to the inner forestay I couldn't trim the sail correctly, as the traveler couldn't go back far enough.

Just something to consider, not seen it mentioned thus far. Inner forestay is 1.5m back from my FS.

[smurphny]

Boy, using a halyard winch sounds really convenient but don't think putting that kind of continuous strain on these small winches and the turning force on the mast is wise. Been thinking of rigging an inner stay. Going to the mast top is a great idea to avoid having all the additional gear required for running backstays. Would also clear the radar dome. My boat looks as if someone had an inner stay running from the spreaders. It has a heavy, bronze mast contoured eye there but it doesn't look as if there were ever additional backstays. Guess they depended on the lower shrouds. There is a heavy pad eye about 3' from the bow plate but it has no attachment below down to anything, just a backing block. Has anyone seen or dealt with this on an A35 or similar old full displacement hull?

[SV Demeter]

Okay the method I was prescribing using halyard as part of the tension system does require some additional work and yes you need to make sure your kit is up to the task but this is certainly feasible.

1. As far as tension goes a halyard winch will get you plenty of tension on the stay if you are talking about your typical moderate to heavy disp. cruising boat. Have you looked at your headstay sag beating in 20kts lately? If you are looking for a bone taught leading entry I suggest you are not running a cruising boat. I have used this method on plenty of boats and been able to point as well as I would expect given the hull form and other factors.
2. As far as stregth goes lets remember that this setup is not holding up your rig like a forestay. It is subjected to the loads of the staysail. Use a clutch if you dont trust the winch. Yes make sure your halyard sheaves are up to the task as well. By using the halyard winch you should not be able to subject them to any significantly differnent loads than you would be hoisting a regular sail. I prefer to use a dedicated sheave box fitting and stay attachement point and not the existing masthead kit.

3. Lastly if you cant get the sheet lead right try using a tack pennant.

Of course there will be others who prefer wire and stainless adjusters and thats fine in my opinion too. Just not the route I prefer. Good luck all.

[malbert73]

Great ideas all!
I tend to like a fixed attachment at the top, rather than using winch to tension through a halyard sheave.

If my rusty physics knowledge serves me, tensioning the shroud with the halyard winch will also double the compression loads on the mast, not that I am really worried with my cruising rig.

I also like tensioning the stay independent of the sail, as I think my staysailwill wrinkle vertically if I tension it as much as the stay.

[smurphny]

If my rusty physics knowledge serves me, tensioning the shroud with the halyard winch will also double the compression loads on the mast, not that I am really worried with my cruising rig.

Great point Malbert73. Would like to hear from someone who has calculated the forces involved in using a halyard winch to tension a temporary stay. Was thinking of trying this but have a deck stepped mast and certainly would not want to put excessive load on the beam below. Wondering if the load would exceed that produced by the 160% genoa or asymmetrical spinnaker.

[ack]

I attended an offshore sailing seminar last week run by a pro sailor from Rhode Island (Joe Cooper). He's a big proponent of dyneema solent stays on cruising boats. He suggests rigging a fairly simple block and tackle on the deck to tension the stay. This is a far better solution than needlessly doubling the compression load on the mast, and it's inexpensive. Lots of information here and elsewhere on his site:

PracticallySailing presents Joe Cooper

[estarzinger]

Originally Posted by ack

(Joe Cooper). He's a big proponent of dyneema solent stays on cruising boats. He suggests rigging a fairly simple block and tackle on the deck to tension the stay.

Joe's a good guy.

His description of the tackle system does steps around the two most difficult parts of the set-up: #1 You need a pretty significantly strong jammer to hold the tackle line. It depends on the boat size, but the Spinlock ZS jammer is the hardware of choice. #2 You need to be able to create a fair lead for the tackle line from the innerstay back to a winch - that's easy on some deck layouts but harder on many others.

For the tackle rope . . . you wil want to use uncovered dyneema (as he shows in his pics) for the area that is in the tackle (to reduce friction and chafe) BUT you will need it covered where it is held in the clutch (to avoid slipping).

Just as a small detail on dyneema innerstays - to make the end splices properly you need a quite long bury. That bury length will be double the diameter of the rest of the line and you need to factor that into your hank sizing, so the hanks don't jam on the extra diameter. Its not a big problem, but something to be aware of.

Originally Posted by smurphny

Great point Malbert73. Would like to hear from someone who has calculated the forces involved in using a halyard winch to tension a temporary stay.

Hard to calculate because the peak loads will be shock loading due to mast whip - which will depend on the mast section. But I would venture to guess that this will NOT be a significant extra loading on any properly built mast step.

The things that will break in order are #1 any halyard clutch - clutches are not typically designed to hold stay tension, #2 the halyard sheave - sheave might deform or it might be pulled out of the mast, #3 the winch pawls.

If you used a 2:1 halyard you would both reduce the compression load and increase the possible stay tension.

Another operational thing to think about with the method is that the stay is NOT tensioned when you are trying to hank on the sail and hoist it. So the whole thing is going to be flopping/flogging around.

Also again related to the splice bury - in this method the bury will probably be going thru the sheave at the bottom of the stay (depending on how close to the deck you want the tack) so the sheave needs to be sized for double the dyneema line diameter.

Do note that you need a specially built or modified staysail for this to work - with a high modulus rope built into the luff. You CAN NOT use this technique with an unmodified normally built staysail - the luff will just be stretched and pulled apart.

[Weyalan]

I am kicking this idea around for Insatiable. Is there any compelling reason why one couldn't employ a multiple block system for purchase on the bottom of the stay. That way you can get plenty of tension without significant load on your jammer. I guess that you would need reasonably substantial load rating blocks, but something like a cascading vang should work, no?

I assume that with Dynex or something similar, you aren't going to get any stretch, so its not as though you need a long travel, so your cascade or purother purchase system can be fairly close to the deck.

[estarzinger]

Originally Posted by Weyalan

I am kicking this idea around for Insatiable. Is there any compelling reason why one couldn't employ a multiple block system for purchase on the bottom of the stay.

Excellent approach if you can get a fair lead for the line from the chainplate to a winch. It depends on the boat size, but on most cruising boats it would be hard to get enough mechanical advantage to be able to pull it by hand (you would need somewhere between 40-60:1).

[smurphny]

Thanks for that Beth and Evans. Good points. I like the idea of coming right off the masthead instead of lower, eliminating the need for extra backstays but don't think I'd use the sail-in-the-stay idea. Am wondering if a small come-along, strung with s.s. cable, would be a quick way to attach an inner forestay. Usually have a couple of these on the boat anyway. Don't know if the effort is worth it though and how much advantage over the small storm jib this would be? It also may throw off the mechanics of heaving-to, having the jib's center of effort so far back.

[Weyalan]

Originally Posted by estarzinger

Excellent approach if you can get a fair lead for the line from the chainplate to a winch. It depends on the boat size, but on most cruising boats it would be hard to get enough mechanical advantage to be able to pull it by hand (you would need somewhere between 40-60:1).

Do you have a ballpark figure for the required tensile loads? If you are talking about 50:1 on what I could reasonably apply - say 80kg, that would indicate 4 ton tensile, which, factoring in some for additional loads in heavy weather, is probably 5+ ton SWL blocks... which rather quickly becomes an expensive exercise!

I had been assuming that the tensile load would be in the 1 - 2 ton region, which would be lightly less spendy in the hardware department.

If the figures are around the 5 ton, I may need to rething my hard point. I was working on the assumption that a deck pad directly over a ring frame, with stainless steel angle brackets below deck would be sufficient, but I might need to revisit this assumption as well.

[Weyalan]

Originally Posted by smurphny

Thanks for that Beth and Evans. Good points. I like the idea of coming right off the masthead instead of lower, eliminating the need for extra backstays but don't think I'd use the sail-in-the-stay idea. Am wondering if a small come-along, strung with s.s. cable, would be a quick way to attach an inner forestay. Usually have a couple of these on the boat anyway. Don't know if the effort is worth it though and how much advantage over the small storm jib this would be? It also may throw off the mechanics of heaving-to, having the jib's center of effort so far back.

It is my understanding that moving the centre of effort of the jib aft is desirable because, by the time you use a small jib on an inner forestay you probably have reefed your main, which moves the centre of effort of the main forward, so the two balance out...

[smurphny]

Originally Posted by Weyalan

It is my understanding that moving the centre of effort of the jib aft is desirable because, by the time you use a small jib on an inner forestay you probably have reefed your main, which moves the centre of effort of the main forward, so the two balance out...

Yes, true but since increased jib pressure (as opposed to the pulling draft created between jib and main) is needed to heave-to, and "backing" the jib is sometimes needed to avoid coming about, just wonder whether enough forward pressure would be created by a small jib placed much further aft.