Storm jib size

A

Avocet

Well-Known Member
Joined
3 Jun 2001
Messages
30,549
Location
Cumbria
Visit site
I've just been looking through the RYA's "Yacht Safety" booklet and they appear to be recommending a storm jib with a leech length of about 0.05 times that of the Genoa!

On my 27' boat that means I need a storm jib with a leech length of about 0.4m (or about 16")!

Am I reading it right?

<hr width=100% size=1>
 
Nope!

Its says a heavy weather jib should be 0.135 x C and a Storm jib should be 0.05 x C where "C" in both cases (there's a little diagram) appears to be the leech measurement!

yours confusedly,

Avocet.



<hr width=100% size=1>
 
My storm jib (which is too large for genuine F8-9 conditions) is 64 ft2 on a 100% foretriangle of 185 ft2.

Of course your genoa will be a deck-hugger, whilst your storm-jib will set on a strop and be a high-clew yankee cut.

I still cannot reconcile that with 0,05 of the leech-length - it's more likely to be about 0.15.

<hr width=100% size=1>
 
perhaps...

they actually mean clew diagonal (clew - luff measurement). that would be a bit more like it but still seems a bit weeny.

i seem to recall my last storm jib had a clew diagonal of around 1m compared to 9m for the big genoa (39 ft boat). it took me to windward in a F9 so it must have been OK.

not strictly comparable but i presently use the wing mast as storm 'canvas', it has an area of 10 m sq. (again 39 ft boat)

<hr width=100% size=1>
 
I seem to recall the limits are defined in terms of the height of the foretriangle squared.

<hr width=100% size=1>
 
As an example, if your foretriangle is 35 feet high, the recommended maximum size of the storm jib would be 0.05x35x35 , or about 60 square feet.

<hr width=100% size=1>
 
That sounds more sensible but it's not what the diagram in the RYA booklet appears to be suggesting!

<hr width=100% size=1>
 
Sailmaker's recomendations:
Boats 26'-28'
Luff 16', Leech 12', Foot 7.6', Area 48 sqft, 8oz cloth.
Boats 29'-32'
Luff 18', Leech 14', Foot 8.6', Area 62 sqft, 8oz cloth.


<hr width=100% size=1>
 
Per RORC (which is derived from/consistent with ORC or ISAF now):

a storm jib of area not greater than 5% height of the foretriangle squared, and luff maximum length 65% height of the foretriangle

<hr width=100% size=1>
 
Just to clarify the previous definitions quoted (per RORC special regs) apply to only the significantly more exposed races (for Example Fastnet, Vendee,STAR, Route du Rhum, Jules Verne).

The definition below is for Cat 3 races and maybe more appropriate. Take note of the recomendation to avoid ultra high tech - they disintegrate fast, and transfer higher loads to the boat as there is no give in the material. I've put the RORC definitions below the ORC (note the classes M is multihull, 0 is open ocean, 1 is way offshore, 2 is offshore (such as fastnet), 3 is what most races are (Coews-Dinard, Morgan Cup to Cherbourg), 4 is inshore and coastal)

The Official definition (from ORC special Regs 2002) is as follows:-

4.26 Storm & heavy weather sails

4.26.1 design

a) It is strongly recommended that owners consult their designer and sailmaker to decide the most effective size for storm and heavy weather sails. The purpose of these sails is to provide safe propulsion for the yacht in severe weather -they are not intended as part of the racing wardrobe. The areas below are maxima. Smaller areas are likely to suit some yachts according to their stability and other characteristics.

4.26.2 high visibility

a) It is strongly recommended that every storm sail should either be of highly-visible coloured material (eg dayglow pink, orange or yellow) or have a highly-visible coloured patch added on each side; and also that a rotating wing mast used in lieu of a trysail should have a highly-visible coloured patch on each side

4.26.3 materials

b) It is strongly recommended that a heavy-weather jib does not contain aromatic polyamides, carbon and similar fibres other than spectra/dyneema
the following shall be provided:-

4.26.4 for each storm and heavy-weather sail, sheeting positions on deck

4.26.5 for each heavy-weather jib, a strong securing method (which does not comprise or depend upon a luff-groove device) for attachment to a stay

4.26.8 a heavy-weather jib of area not greater than 13.5% height of the foretriangle squared, and without reef points (or suitable heavy-weather sail in a yacht with no forestay)

4.26.9 either - mainsail reefing to reduce the luff by at least 40%, or a storm trysail as follows:-

a) capable of being sheeted independently of the boom and of area not greater than 17.5% mainsail luff length x mainsail foot length. It shall have neither headboard nor battens. However a storm trysail is not required in a yacht with a rotating wing mast which can adequately substitute for a trysail

b) the yacht's sail number and letter(s) shall be placed on both sides of the trysail (or rotating wing mast if fitted) in as large a size as practicable

c) aromatic polyamides, carbon and similar fibres shall not be used in a trysail or storm jib but spectra/dyneema and similar materials are permitted

d) it is strongly recommended that a trysail track should enable the trysail to be hoisted quickly

RORC Special Regs

4.26 Storm & Heavy Weather Sails
4.26.1 design
a) It is strongly recommended that owners consult their designer and sailmaker to decide
the most effective size for storm and heavy weather sails. The purpose of these sails is to
provide safe propulsion for the yacht in severe weather -they are not intended as part of
the racing wardrobe. The areas below are maxima. Smaller areas are likely to suit some
yachts according to their stability and other characteristics.
**
4.26.2 high visibility
a) It is strongly recommended that every storm sail should either be of highly-visible
coloured material (e.g. dayglow pink, orange or yellow) or have a highly-visible coloured
patch added on each side; and also that a rotating wing mast used in lieu of a trysail
should have a highly-visible coloured patch on each side
**
4.26.3 materials
a) Aromatic polyamides, carbon and similar fibres shall not be used in a trysail or storm jib
but spectra/dyneema and similar materials are permitted
b) It is strongly recommended that a heavy-weather jib does not contain aromatic
polyamides, carbon and similar fibres other than spectra/dyneema
the following shall be provided:
**
**
4.26.4 sheeting positions on deck for every storm and heavy-weather sail **
4.26.5 on every storm or heavy-weather jib, a strong securing method (which does not comprise or
depend upon a luff-groove device) for attachment to a stay
**
4.26.6 storm trysail
a) a storm trysail capable of being sheeted independently of the boom and of area not
greater than 17.5% mainsail luff length x mainsail foot length. It shall have neither
headboard nor battens. However a storm trysail is not required in a yacht with a rotating
wing mast which can adequately substitute for a trysail
b) the yacht's sail number and letter(s) placed on both sides of the trysail (or rotating wing
mast if fitted) in as large a size as practicable
c) It is strongly recommended that a trysail track should enable the trysail to be hoisted
quickly
MoMu0,1,2
(entire
section
4.26.6)
4.26.7 a storm jib of area not greater than 5% height of the foretriangle squared, and luff
maximum length 65% height of the foretriangle
MoMu0,1,2
4.26.8 a heavy-weather jib of area not greater than 13.5% height of the foretriangle squared, and
without reef points (or suitable heavy-weather sail in a yacht with no forestay)
**
4.26.9 either: - a storm trysail as in 4.26.6 above, or - mainsail reefing to reduce the luff by at least
40%.


<hr width=100% size=1>
 
You must log in or register to reply here.

Share this page

Top