Inner forestay

[Danny]

One thing to check with detachable inner forestays is the suitability of the attachment point. If there's no support under the foredeck at the point of attachment the deck may lift or deform with the tension on the stay. The attachment point should either be at a bulkhead, with the strain taken on the bulkhead rather than the deck, or else there should be some method of taking the strain down to the hull. At the very minimum there should be a large pad under the attachment point to spread the load as far as possible.

The same applies to a babystay to a lesser extent, but hopefully this would have been taken care of in the original rig design.

 

[BlueSkyNick]

On the new boat, we have a spare genoa halyard (wire) and a very robust ring welded onto the after edge of the bow roller.

I am hoping this is suitable to handle the storm jib, (which is included) or even a No.3 (which doesnt exist).

Would have to winch the second halyard bar tight, then use spinnaker halyard to hoist storm jib.

Previos owner advises this was the intended method.

Is this sensible?

 

[Danny]

It's OK but not as good as a stay fixed at the masthead. Using a halyard means twice the additional compression forces on the mast for the same amount of tension.

 

[BlueSkyNick]

Good point, but there again if it is storm jib conditions, the main would be well reefed too.

 

[tome]

Don't think you'd have a hope in hell of getting sufficient tension on a halyard

 

[Guest]

Use Spectra for the halyard - then you can get plenty of tension /forums/images/graemlins/smile.gif

 

[Phoenix of Hamble]

Second Tomes comment...

Nick, I had the same approach for the storm sail on Magna Carter, with a sail with a sewn in wire luff, on a rope halyard....

I winched and winched until I was purple in the face, on a large winch with 3 speeds, and still had a huge sag in the luff...... completely inapprpriate for a high wind sail, which could do with the luff being bar tight!

My approach on the next boat will be a highfield lever if I need a removable inner forestay.....

PS, as an aside... great thread... really interesting and informative.... thanks all!

 

[Guest]

Magnacarter, I have a Highfield lever on my inner forestay, but it's hard to get proper tension on a removeable forestay without messing around with spanners etc. on a pitching foredeck - not really practical in a gale. So the inner forestay is essentially used for the hoist. Luff tension is achieved by winching in the Spectra halyard which is very low stretch - I found it no problem to get plenty of tension in the luff this way - in fact the danger has rather having to be careful not to over-tension and destroy the sail! Obviously it helps to have a decent halyard winch. Spectra isn't cheap though.

 

[Aja]

The correct termiology, I think I'm right in saying, is where an inner forestay is fitted from at or near the top of the mast to abaft the normal forestay fitting is called a 'slutter' rig.

Not to be confused with baby or forward lower stays.

Donald

 

[Guest]

Post deleted by danfoley

 

[tome]

This is true with a cutter rig because the inner attaches to the mast some way below the forestay - you most definitely need the runners

On an inner forestay set up like ours, the attachment point at the top of the mast is very close to the forestay and runners aren't therefore needed

 

[fireball]

Assuming the halyard is fastened at the bottom of the mast then I can't see that you will "double the compression". Even if it is led aft and cleated on the coach roof then I would think that the compression on the mast is going to be the same (just an additional aft element!).
But as it is unlikely that you'll get sufficient tension I suppose it is a mute point ... anyone tried cascading blocks to get additional purchase?

 

[Phoenix of Hamble]

Thats interesting... my plan was to have a hank on sail, and set the inner forestay up well in advance... hopefully prior to a gale!... but the law of sod, and all that..... /forums/images/graemlins/grin.gif

 

[tome]

A better way of getting the tension right (agree it's not easy) would be to have an adjustable backstay which you could slacken off whilst setting the inner then wind it back on. A hydraulic tensioner would be ideal

There's no way I'd want to put that tension through the halyard and sail luff

 

[Danny]

[ QUOTE ]
Assuming the halyard is fastened at the bottom of the mast then I can't see that you will "double the compression".

[/ QUOTE ]If the halyard winch is on the mast then the added compression on the mast (compared to a stay of equal tension) is still doubled - it's just not causing any extra load at the foot of the mast.

The doubling is because the sheave at the masthead has the downward force due to the required tension on both sides.

As you say, it's probably a mute point in view of the amount of tension one's likely to be able to generate with this method.

 

[Roberto]

\"Race\" ideas

I have an inner removeable forestay attached a few cm below masthead, with a lever tensioning device on deck, a few cm behind roller furling.
It works correctly, a bit of fiddling with the backstay if one wants a perfect tension but mostly happy with it.

I want to have the possibility of raising a staysail closer to the mast (and basically not having to go forward), whose head will be attached on the mast at about the higher spreaders height, and tack point about at the anchor locker aft bulkhead.

As I do not want to add all that weight aloft, that's my solution (not yet fully implemented as still have a couple of things to decidce) -well not really mine I simply copied it from racers:
running backstays of course, made in high modulus fibre, I used a T terminal into a simple slot in the mast with a backing plate; easily removable but not too heavy anyway

on deck, a furler drum: attached to this, a heavy weight staysail whose luff is sewn around an anti torsion cable (to transmit torsion to the upper swivel; it is a funny cable, if one has 10m of it lying on the ground and turns with the thumb one extremity, the other one 10M away turns as well)

no stay

the sail is hoisted either with:
a) a double purchase block, I calculated breaking strain of the whole lot should be around 3-4 th kg, depending on amount of catenary, an acceptable working tension can be reached with a 40 winch; as the halyard would be brought on deck this would increase mast loading; or

b)what they call a "hook": the sail is hoisted, its head hooks into a device up there in the mast, and the required luff tension is obtained with a tackle on deck; advantage is mast loading stays lower.

Sails (storm jib etc) are kept furled, drum attached, tension applied and then unfurling.
No more need to go forward to handle all those jib hanks one by one..

The problem is -especially with boats having loads of 2-3 tons or more on their stays, that blocks and tackles are very expensive... I just have had a long talk with a mast manufacturer, as a technical solution is absolutely feasible and with very good results in sail performance


/forums/images/graemlins/smile.gif

 

[Guest]

Yes, I also tend to slack off the backstay to get as much tension as I can with the Highfield on the inner forestay. The problem is that what is easy in harbour is much harder at sea - the "whip" effect of the forestay bucking back and forth in a seway while you try to tighten it means that it can be impossible to close the highfield, even with the backstay slacked off, at sea. Anyway, in a gale you want it to keep it as simple as possible

Solution is either to set it up in harbour before leaving, in which case you can get it nice and tight at leisure. Or, set it up at sea at an early stage, probably heaving to, or heading downwind for a moment while you bring on the pressure on the highfield. Going downwind probably an especially good idea as the main can help to push the mast forward while you tighten, as well as giving a much more comfortable foredeck. Distance lost to leeward would probably be worth it in normal circs. Also use a staysail (we use a No.4) so that you're setting it up in F5/6 conditions, not when it's already storm job time at F8!

 

[Twister_Ken]

Brian,

I forgotten exactly how they do it, but fractional racers with runners would have some some bungee intro'd into the set-up somewhere which would let the runners 'stretch' behind the boom when freed off. A quick wander around a 'hot' marina should show you how it's done.

We were more traditional on the big boat I raced, and had runners on snatch blocks, which could be unhooked and taken forward when not needed.

 

[tome]

Agree - we try to set it up in harbour if we think we'll need it, even if we are still using the genoa. It's not fun having a stay flailing about in a rising wind

This year we'll fit an extra set of cars so we can have both sets of sheets rigged, then the inner can be bagged and hanked on with sheets all ready to go and the halyard tied off at the mast. This should avoid any visits to the foredeck

 

[tome]

I've used turning blocks at the stays with a small line lead back to the cockpit to stow them when not in use (on an old gaffer I had)