how to rig an inner forestay which MUST be parallel to main forestay?

[psk125]

We sailed on a sloop that hoisted a solent jib on the regular forestay when the wind piped up (25kts). When the wind piped up some more (35kts), we reefed it by lowering it a notch and sheeting to a clew higher up - like slab reefing a mainsail. No fuss, no muss.

[SVTatia]

Originally Posted by waterman46

Why a spacer inside the mast? I added a non-parallel inner stay about 2' below the mast top. Drilled a hole through both sides of mast and ran a bolt through. No spacer needed, just snug the nut on that bolt up against the mast but not real tight, and use either two nuts tightened together with a lockwasher or a nyloc nut. Bolt runs through ends of two SS straps that meet together in front of the mast to take the inner stay pin. I think I bought that SS mast tang part as an assembly somewhere.

Mast has a rather strong cross-section and with only 2' separation below the backstay I have not noticed any mast bend when closehauled with staysail in a stiff breeze.
Running backstays are a big expense and a pain to use.

We use a detachable inner forestay with lever tightener. Wonder if you want to leave that inner forestay in place permanently?

Running backstays is a pain in close quarters but for passages not a problem. I know, I sailed with them for many years. In tacking conditions I just did not bother with the staysail.

If you are carefull not to tighten the thru bolt more than needed, and making sure the nuts will not back out than it is okay as you've described.

My intention is to use the inner forestail for the storm jib, so if it is at the spreader or jts above it would be better to manage the wire (shorter) when not in use. Too far up may interfere with tacking if the staysail is used with the genoa.

[Jim Cate]

We sailed on a sloop that hoisted a solent jib on the regular forestay when the wind piped up (25kts).

A Solent jib is by definition NOT hoisted on the forestay, but on a separate stay whose head is near the forestay's and whose deck termination is somewhat aft of that of the forestay.

So, not sure what you are talking about.

In the distant past, long before furling sails, we tried out slab reefing jibs. Never found them satisfactory, for containing the bunt of the sail proved nigh impossible for more than very s hort intervals, and sail shape wasn't good either. Further, setting the reef on a pitching fordeck was damn hard and quite scary. In the long run, changing headsails was a better method of reducing sail area.

Jim

[fxykty]

Originally Posted by Jim Cate

A Solent jib is by definition NOT hoisted on the forestay, but on a separate stay whose head is near the forestay's and whose deck termination is somewhat aft of that of the forestay.

So, not sure what you are talking about.

In the distant past, long before furling sails, we tried out slab reefing jibs. Never found them satisfactory, for containing the bunt of the sail proved nigh impossible for more than very s hort intervals, and sail shape wasn't good either. Further, setting the reef on a pitching fordeck was damn hard and quite scary. In the long run, changing headsails was a better method of reducing sail area.

Jim

Well, our French-origin cat with only one forestay calls its self-tacking jib a solent. So it’s likely that.

Also agree that reefing a headsail only the days of furling sails seems silly. Either have multiple stays and different sized sails on each of them, or stick with a single furling sail and is a temporary stay for a staysail and/or storm jib.

[ferrailleur]

Originally Posted by Adelie

If the stays are parallel then the triangles are similar (in the geometric sense).
So J1/J2 = I1/I2 and J1/I1 = J2/I2.

J2 = J1 - X

I don’t care to do the rest of the derivation, too much like being in high school math again.
What are I1, J1 & X?

thanks... please review my calculation
I = 34'
J = 11 1/2'

I have 47" from bow to my inner stay attachment point
which is approx. 34% of J

My bail attachment on mast should be 34% of I which is 11.33'
the bail on pic will be attached at 11.33' from top of mast.

WILL THE INNER STAY AND FORETAY (BOW TO TOP IF MAST) BE PARALLEL?
Thanks

the pic shows a pad eye (taped for the pic) which will secure a removanle baby stay.

[waterman46]

Originally Posted by ferrailleur

thanks... please review my calculation
I = 34'
J = 11 1/2'

I have 47" from bow to my inner stay attachment point
which is approx. 34% of J

My bail attachment on mast should be 34% of I which is 11.33'
the bail on pic will be attached at 11.33' from top of mast.

WILL THE INNER STAY AND FORETAY (BOW TO TOP IF MAST) BE PARALLEL?
Thanks

the pic shows a pad eye (taped for the pic) which will secure a removanle baby stay.

Did you really mean to have a baby stay? Baby stay is not same as inner forestay. Baby stay terminates on deck very close to the mast, and is sometimes found on bendy mast rigs, usually high performance boats.
I added removeable inner forestay and used the same type of bracket on the mast that you show in picture. It works fine. Having the removeable inner forestay is really great. Allows you to clear the foredeck most of the time, but when wind is up, it is not hard to go forward and attach it. We have a hank-on fore-staysail which remains attached to the removeable stay at all times. It is contained in a bag on deck and the whole apparatus is secured to the forward lower shroud when not in use.

[ferrailleur]

Originally Posted by waterman46

Did you really mean to have a baby stay? Baby stay is not same as inner forestay. Baby stay terminates on deck very close to the mast, and is sometimes found on bendy mast rigs, usually high performance boats.
I added removeable inner forestay and used the same type of bracket on the mast that you show in picture. It works fine. Having the removeable inner forestay is really great. Allows you to clear the foredeck most of the time, but when wind is up, it is not hard to go forward and attach it. We have a hank-on fore-staysail which remains attached to the removeable stay at all times. It is contained in a bag on deck and the whole apparatus is secured to the forward lower shroud when not in use.

the removable inner forestay and jib halyard will be brought back to mast when not in use. The mast bail shown on pic has a large round eye for attaching a double block in front of mast for inner forestay and halyard.

the baby stay (pad eye taped on pic) will will dynema to support mast a this location. They will hook on a lower shroud pad eye.... they will be removable when not in use.

Thanks for the input.... Do you think that my calculation is OK for parallelism?

[Quebramar]

I also have set a removable inner stay, the attachment points were pre-defined and I am not 100% sure that both stays are fully parallel.

Could you enlighten many of us about the reason why you are insisting on parallelism? If both headsails are to be used simultaneously that would be required, but otherwise?

[waterman46]

Geometry was my favorite subject in high school, but there is a much easier way to do this.

The first and biggest item is location of inner forestay on deck. This will depend on the method of deck reinforcement to be used, and location of hatches, windlasses, cabin top, bulkheads, etc. Don't need a sailmaker for that. Do it first.

The mast is (was?) out of the boat. After you know the attachment point on deck of boat, you can lay the mast and the forestay flat on the ground and use the following method to assure a parallel inner forestay.
First, on the boat, put a string from forestay attachment point to the mast base on deck. This string will be nearly horizontal, it doesn't matter, but lets' call it the horizontal string. Then use a second string and weight, to get a vertical from the horizontal string down to predetermined inner forestay attachment point. Measure total horizontal string length, height of horizontal string above new innerstay attachment point, distance from vertical string to mast base. On the ground lay out the same dimensions using your mast and forestay, to determine a simulated location on the ground, for the inner forestay attachment point. Now take a string to represent your inner forestay, lay it out between the simulated attachment point to the mast, and adjust it on the mast for parallel to the forestay. No rocket science, not even geometry, just a tape measure.

Now you need to determine the sail dimensions.

Actual SA of staysail is not critical, we know it will be considerably smaller, within reason, than the genoa, and that is the goal. Change the windspeed a couple knots and you get a different ideal sail area. It's never perfect.

A start would be to calculate force on the sail at various windspeeds compared to his existing genoa. You should already know what windspeed You have to start reefing the genoa, or at what point the reefing causes poor sail shape. Calculate force on known genoa area for that windspeed. Now pick a higher windspeed as the maximum the staysail will be used at, then calculate sail area of staysail for the same force at the higher windspeed.

After the rig is up and the inner forestay installed, then hoist small ropes or strings on your staysail halyard to figure out where the leech of your new foresail will be located, using the desired sail area. The leech has to clear the spreaders, inside or out, and it depends on the design of the rig. Since we have shroud chainplates outside the hull, I had to have the leech clear the spreaders with the sheet inside, for closehauled trim. You may be able to run the sheet outside the shrouds, which is much better, but may limit your closehauled sheeting angles. I would think a staysail usually needs to be sheeted inboard.

Or you can pay a sailmaker to do it all. I did my own and maybe I was lucky but it works just fine.

[waterman46]

Originally Posted by ferrailleur

the removable inner forestay and jib halyard will be brought back to mast when not in use. The mast bail shown on pic has a large round eye for attaching a double block in front of mast for inner forestay and halyard.

the baby stay (pad eye taped on pic) will will dynema to support mast a this location. They will hook on a lower shroud pad eye.... they will be removable when not in use.

Thanks for the input.... Do you think that my calculation is OK for parallelism?

OK I misunderstood but now know you actually do have a baby stay in addition to your new inner forestay.
Your calculation for forestay using a proportional approach may be a little off, because the actual attachment point of inner forestay on the deck will not be in the direct line perpendicular to the mast as "J" is measured. Due to slope of deck, attachment point is very likely below the horizontal line of "J". An accurate calculation can be done, if you know vertical distance of the attachment eye below the horizontal line of "J" and the horizontal distance of attachment point to the forestay along this line of "J". Don't trust any published dimensions, go measure these things on the boat.
It may be a problem to secure your inner forestay to the mast when not in use, as you mentioned. That new stay will extend considerably below the base of the mast when brought aft, so unless you have some unusual way to secure it, it will have extra length that will flop around and bang against the mast. Better secure it to chainplate or turnbuckle of forward lower shroud.

[ferrailleur]

Originally Posted by Quebramar

I also have set a removable inner stay, the attachment points were pre-defined and I am not 100% sure that both stays are fully parallel.

Could you enlighten many of us about the reason why you are insisting on parallelism? If both headsails are to be used simultaneously that would be required, but otherwise?

The parallelism is in my view an important factor of the look (appearance). It doesn't affect the operation of the headsail. My sailmaker will determine the cut and size of that sail in relation to the main with one or two reefs. The head of the jib will certainly not be reaching the level of the bail.
Hope that make sense.
Thanks