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Sail & Rigging - Storm jib for a 41
07 April 2014 - 18:01
#1
Join Date: 27 August 2009
Posts: 44

Storm jib for a 41

To Forum members,

I am to register Antares (S&S 41/11) for the Arm Men Race late May and we intend to sail two-handed. We are planning for potential heavy weather and were looking for advice on having a storm jib on a baby stay. The questions I have are the following:

1. On Antares I have 2 plates on the deck. Ideally, should I use the fore-front one (smaller in appearance but above a partition in the inside, below the deck), or the one more in the back (larger but with no partitioning below deck) to fix the baby stay? The former would be more convenient for me as I have a radar in the mast and the existing cable that can be used as a baby stay needs to be fixed on the front plate to avoid any friction.

2. What kind of tackle should be used to have the ability to strenghten the baby stay? Any recommandation on minimum equipment required for a S&S 41?

3. Likewise, what block/pulley and schackle should we use to ensure enough strenght? 

Many thanks in advance for any input you may have.

Christophe

Antares (S&S 41/11)

08 April 2014 - 11:12
#2
Join Date: 02 January 2008
Posts: 1547

Dear Christophe
The highest loads in the storm jib will occur when the mainsail is bottom reefed, or a trysail is used. If you could give the dimensions of the main/trysail and the storm jib this enables loads to be worked out.
Does your mast have runners?
Kind regards
Lars

08 April 2014 - 11:27
#3
Join Date: 27 August 2009
Posts: 44

Dear Professor,

Many thanks for your input.

As to the size of the jib, I don't have measurements with me. I assume this is rather standard. Don't you think? Antares is short rig / 1 spreader.

On your other question, if by runner you mean a running backstay, no, I have no runner.

I do hope this will help you giving me further advice.

Kind regards.

Christophe 

08 April 2014 - 20:22
#4
Join Date: 02 January 2008
Posts: 1547

Dear Christophe
This race is Category 3, i.e. mainsail luff reefing to 60% P, and storm jib carried. The bottom reefed mainsail area is then 17 m2, and storm jib 14 m2 if the jibstay is attached at 2/3 of I and J.
Assuming these areas the reefed main sheet and halyard load will roughly double compared to sailing with overlapping genoa, to 1 ton, and jib sheet and halyard load be almost the same as with the genoa, 1.1 ton.
The reefed mainsail headboard will be near the jibstay attachment, and tension the jibstay to about 1.5 tons, this will cause it to sag 3.3%. Sag can be reduced a little by tensioning the main sheet more, but care has to be taken not to overload the headboard, sheet blocks or jibstay. Do you plan to use wire or rope for the jibstay? With rope soft jib hanks are required.
The loads mentioned above are SWL's, not breaking loads, and it is suggested you check your equipment in this respect.
How does this sound?
Kind regards
Lars

09 April 2014 - 15:08
#5
Join Date: 27 August 2009
Posts: 44

Thank you Professor for this.

If my understanding is correct (i) I need to have a tension of 1.5T on the Jib stay and (ii) I should have a maximum of 1.1T on the storm jib.

Going back to my first initial question: Is the plate closest to the bow on the fore-deck (above a partition in the inside separating the foreward cabin from the chain locker) OK to bear with these loads? If such were the case then I just need to buy the right material to build a halyard.

Kind regards.

Christophe

09 April 2014 - 16:48
#6
Join Date: 02 January 2008
Posts: 1547

Dear Christophe
You are right in your assumptions.
I must confess that I expected a protest from you, because these are racing loads, and they are very high for a 41. In cruising conditions about half would be used.

What size are your genoa halyard winches and main sheet winch, and how many parts on the main sheet? These details determine the loads that can be achieved.

The attachment point above the forepeak bulkhead is OK, provided the deck fitting is strong enough. Would you have a photo and some dimensions for it?

The recommendation is to distribute the loads from the deck fitting over a larger area. This can conveniently be arranged by adding a transverse L-profile below deck into the corner between bulkhead and deck on the forward side, and have some or all of the fitting bolts going through the horizontal part of the L.
Kind regards
Lars

11 April 2014 - 09:49
#7
Join Date: 02 February 2007
Posts: 202

Christophe,
you will find drawings of the installation on our 41/022 below. Ours is a tall rig and we never had any problem. The gib stay is attached to the plate under the stern wit two 12mm bolts with eye nuts. The only difficulties to face are: drilling two 12mm holes in the plates (through the existing holes of course) and adjusting the right thickness of the inside plates between the nuts and the polyester of the hull. The plate to which the flying stay is attached comes through the deck, just behind the top plate.
I hope this will help.
Kind regards.
Philippe

11 April 2014 - 09:54
#8
Join Date: 02 February 2007
Posts: 202

Christophe,
second try to send a drawing!

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