What size storm jib?

Tim O

Tim O

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On my list of "improvements to make to the boat" as and when I have the time/money is to fit a removable inner forestay for a storm jib. In all likelihood I will fit this close to the main forestay, with an attachment point on the bow roller fitting where there is an existing hole just behind the current forestay - this to avoid having to fit another strongpoint on the foredeck which is already quite cluttered.

Anyway... my actual question is...how do you determine the correct size storm jib for your boat? are there some simple rules of thumb? What are the "tolerances" either way from the "perfect" size....and if so, would it be better to be slightly too small than too big (logic and fear would dictate so to me!)?

The boat btw is a Colvic Countess 33 foot ketch bilge keeled
 
Couple of thoughts

a) is there a owners association that can help you; and

b) talk it over with your sailmaker
 
I've not got the link right now as I'm writing from my phone, but the ISAF Offshore Regulations give good guidance on size for the storm jib.

They are downloadable as a PDF. They also include things like keeping sheets and a short downhaul permanently attached si that you're not looking around for then when needed.
 
I have a 34 foot boat and bought a second hand hank-on storm jib made by a reputable sailmaker for a very different design of 33 foot boat.

This was in excellent condition bar a few stains, and cost only £100. I was nervous about whether it would be compatible.

Having now used it a few times for real I find it entirely satisfactory and conclude that the "tolerances" are considerable as long as the sail sets.

If I was having one made I would specify one set of reefing points so that with the full sail there would be enough power to, say, get away from a lee shore but that, in a big blow, I could minimise the area.
 
Now called Offshore Special Regulations can be found here

http://www.sailing.org/specialregs

Pick something like Monohull Category 2 and scroll down until you see the bright orange storm sail diagram.

For this category one also needs a "heavy weather" jib which is part way between the standard genius and the storm jib... So perhaps that's a consideration for size as well.
 
If you are considering adding an inner forestay (highfield lever), good idea, and have a storm jib built then,

It will probably be hanked on. You really do not want to be mucking around on the foredeck hanking on a storm jib and then raising it. You will have listened to the forecast and decide that in the fullness of time you will need the storm jib - ideally that is the time to hank on. But it will be too early to hoist. Ask the sailmaker about a bag in which you can keep the sail, hanked on, sheets attached - such that you can hoist and set it from the cockpit (maybe the bag secured closed with Velcro and tied down to the deck, somehow.).

Equally someone might come up with another idea.

I've only ever used a storm jib once, but had a crew of 6. I decided not to use a storm jib another time, unforecast 55 knots, and I left it too late and I was not going on the foredeck in such conditions. we simply reached with a 3 reefed main. We had removed the furling 150% genoa and replaced with a self tacker (sort of No4) in anticipation of the actual forecast - but it was a bit optimistic.

Jonathan
 
There's a problem with a storm jib tacked down to the forestay fitting, Tim.

A storm jib needs to be away from the risk of shipping green water into it and ripping, and also you don't want the centre of effort of the sail too far forward otherwise the possibility of lee helm. CofE should be roughly where the genoa CofE is.

Hence the reason that storm jibs are fitted to an inner forestay, which may or may not be a permanent fitting. The foot of the jib should be cut high to avoid catching water and to provide a bit of visibility underneath it. The jib should have all the fittings (sheets, shackles, wire luff extension, etc) all ready in the bag.

I've seen one with a stainless steel mesh built into the top panel to aid radar detection, but cannot say that would work.


Keep your eye open on ebay and the For Sale forum, as good ones do turn up from time to time :)
 
Martin_J said:
Now called Offshore Special Regulations can be found here

http://www.sailing.org/specialregs

Pick something like Monohull Category 2 and scroll down until you see the bright orange storm sail diagram.

For this category one also needs a "heavy weather" jib which is part way between the standard genius and the storm jib... So perhaps that's a consideration for size as well.
Click to expand...

I think those formulas, unless I miscalculate, produce very small sail areas indeed. Must be intended for pure survival conditions.
If the OP is not planning to sail in such conditions, I think a somewhat larger hanked on foresail on an inner forestay might be more useful. Something that can be hoisted when further furling the genoa is not improving performance any more.
What size to go for depends on many variables, such as how far back the inner forestay attachment point is and how much the main sail area can be reduced.
On my 29' MH sloop the inner forestay is just 0.4 meter behind the main forestay and I have three reefs in the mainsail. The sail I fly on it is a high cut heavy weather jib of 7 m sq (roughly 40 percent of the fore triangle area).
With this sail hoisted the boat is balanced with one reef taken in the mainsail, but I get lee helm with two and three reefs. So my conclusion is the sail is really to big and I plan to change it. What I am aiming for is sail balance at three reefs taken in the main.

bagged.jpg
 
Approaching "..... pure survival conditions" a bagged ready to hoist sail on the foredeck ( as in Babayaga's photo of a lovely boat ) may not stay there as shown for long with tons of green water repeatedly coming over. Mostly however the coastal/short offshore passage need is for a small but much more efficient sail than a baggy deep-rolled genoa, and for this the racing rule storm jib sizes may be too small. These dimensions are designed for true survival conditions, and are you really planning to be there .... ?

Unless you are planning high latitudes work or passages at silly times of year (or both) a small blade jib will probably be used much more often than a true storm jib.
 
All useful and interesting stuff which I will read and digest further and check out the links....

Some answers to queries....n, im not planning to sail in high latitudes or "survival conditions", so Id say I am planning for being prepared JUST IN CASE I was caught short in a serious blow when doing coastal/short offshore passage.

I guess i'm looking for a sail which can be easily deployed once the genoa has been full rolled and the main is fully reefed (2 reef points on mine)....OR as it is a ketch, the main is dropped entirely and i could sail in control with just a storm jib (or small blade as mentioned) on an inner forestay and the mizzen.

Im tryng to avoid the trouble and expense of fitting a true inner forestay attached partway up the mast, as then we are in to fitting not only a deck fitting for it but also running backstays to counter the strain on the mast.
 
Tim O said:
Im tryng to avoid the trouble and expense of fitting a true inner forestay attached partway up the mast, as then we are in to fitting not only a deck fitting for it but also running backstays to counter the strain on the mast.
Click to expand...

Thank you (both) for the kind words.

I seem to remember that sparsmaker Seldén advices that a fitting for an inner forestay can be installed somewhere between 3 and 6 percent of mast length below the mast top without the need for backstays.
 
The Yankee I use hanked onto my inner forestay (on Countess 33) measures:

Luff 33 ft 1 Foot 12 ft 8 Leach 28 ft 5 Area approx 180
(Genoa is 36 ft - 17 ft 6 - 34 ft - 302 sq ft)
I also have a storm gib but I haven't got its size to hand, I've never deployed it.
 
I think for a storm jib your requirement is to be able to sail to windward in conditions where the furling jib has become ineffective. The jib for beating then should relate reasonably to the fully reefed main sail in size. I would suggest a storm jib too small will not do the job. On the other hand if things are really bad and you have stowed the main sail then your only choice is to run or reach then smaller might be better. Until you get to the point where bare poles is the only option when running. So the answer is a variable small for really strong winds, larger for working to windward in just strong winds. So if you reckon you won't meant really strong stuff then larger would be better. olewill
 
LadyInBed said:
The Yankee I use hanked onto my inner forestay (on Countess 33) measures:

Luff 33 ft 1 Foot 12 ft 8 Leach 28 ft 5 Area approx 180
(Genoa is 36 ft - 17 ft 6 - 34 ft - 302 sq ft)
I also have a storm gib but I haven't got its size to hand, I've never deployed it.
Click to expand...

Hi there - I remember you sharing details of your inner forestay arrangement on your Countess with me which is what I am basing the plan to fit a removable one taken to the bow fitting on (from memory...I need to delve back and re-read properly what you sent me)...useful info on the sizes there - if you do get a chance to measure up the storm jib that would be great!
 
BabaYaga said:
Thank you (both) for the kind words.

I seem to remember that sparsmaker Seldén advices that a fitting for an inner forestay can be installed somewhere between 3 and 6 percent of mast length below the mast top without the need for backstays.
Click to expand...

I will check up their info...that's is pretty much what I was thinking...I did read through all their advice some years ago!
 
From my experience of f10 with large seas, the important thing is sail balance. On my.Nab35 sloop ,my rig is triple reefed main and a small banked on staysails on a remobeable inner forestay. She he heaves to and goes to windward if necessary under this rig. Your ketch should.do the same.under jib and mizzen, I would think.
 
I seem to remember that sparsmaker Seldén advises that a fitting for an inner forestay can be installed somewhere between 3 and 6 percent of mast length below the mast top without the need for backstays.
Click to expand...

It appears in their Yacht Product Catalogue - 'Running backstay attachments' - Options 1 and 2.
This is on page 33 of Version 6.... and.... it depends on the mast.
 
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