Can a storm jib be too small

[jskamer]

I'm buying new sails, as we are planning a long (atlantic) passage I've included a storm jib in this order as well. The sailmaker has quoted a storm jib of 6,1m2. This seems small to me on my 43' Jenneau. I used the ISAF calculation to estimate the maximum size and this results in 7,95m2 (using the "new" 3.5% suggested in this report). Now my question is: could a storm jib be "too" small to be effective? It will (if ever necessary) probably be used in combination with the deep reef in my main (leaving about 13m2 of my main).

Any practical experience and insight on this matter is greatly appreciated!

[Shrew]

Short Answer...YES. A Storm Jib sized for a 30 foot boat will be far too small for a 65 foot boat.

I'd be more interested in understanding how the sailmaker arrived at his numbers, if they differed from mine. I would tend to trust the person that does this for a living, over what I dig out of online resources.

I'd at least like to understand why the number is so different. Maybe I'm making a mistake. I'd like to take that opportunity as a learning experience.

[Panope]

2 Data points:

With a 6.9 square meter storm jib, and 7.9 square meter trysail, my 34 foot, 7 ton boat is fully powered at 30 knots true wind (boat is more tender than most other boats).

With a 6.9 square meter storm jib only (no other sails), the boat is fully powered in about 45 knots wind. This is the most wind that I have sailed.

I am GUESSING that at 60+ knots, the rail will be awash under bare poles - so no "sailing". Just surviving and praying to my mommy.

These sizes work well for the way I use them (gale sailing).

If were heading off shore (I am not) in a stiff boat, and wanted to keep sailing in actual storm conditions, then a very small storm jib could be very useful.

[TeddyDiver]

IMO it's the total sail area being more important than an individual sail. The difference here being 21sqm vs 19sqm with deep reefed main and storm jib, not so much..

BR Teddy

besides that, depending how the storm sail is rigged you can hoist it higher to get more power..

[JPA Cate]

jskamer,

It was a few years after the Sydney to Hobart ('98) when so many boats and lives were lost that we had a long chat with our sail maker about how big should storm jibs be. He was of the opinion that the race boats' storm jibs were about twice the size that would represent safety to him. He had been on one of the boats with loss of life, and we were very interested in his thoughts.

The thing that may help you to understand this is that the wind strength are averages. So, say you are caught in a frontal passage, with storm force winds for the average. During that time you may experience 55 knot winds sustained, with gusts 40% stronger (77knots). Since the force of the wind increases geometrically, rather than arithmetically, that is a huge increase in the wind gusts. Now, that storm jib might have you underpowered in 45 knots, but probably not. You're talking all you need is enough sail to control the boat, so you might want 3 reefs for your mainsail, so you'd be able to add a little bit of main if you were underpowered.. If you're really worried about it being too small, perhaps you need a gale sail plus a storm jib.

Ann

[Orion Jim]

I’d be inclined to have a non-overlapping headsail made of slightly heavier cloth and reef it as necessary. When the time comes to replace a headsail with a storm jib I don’t care to be on the foredeck. A temporary inner forestay with a heavy weather sail already rigged and ready for use would be ideal but costly.
I have a cutter rig so I have a lot more options for sail reduction and I’ve ridden out a full gale in the Gulf Stream in relative comfort.

[SailingHarmonie]

Based on your boat, I suspect you have roller furling. If you have never changed a headsail on a roller furler at sea in snotty conditions, I'll tell you it is a nightmare. It is VERY different than a hank-on sail.

With a furling sail, the bottom of the sail is free to blow away as you drop or hoist it. there is no easy way to confine it other than LOTS of hands. What is easy at the dock in a gentle breeze is almost not doable at sea in 40 knots with waves washing the deck. It is for sure not doable by one person, and even two will struggle.

I am betting you will never use the storm sail--ever. It is just too hard to install when you need it.

[crosswire]

My Allied 42 appears to have been retrofitted with a removable inner head stay and a hank on storm jib. The installation had to have been costly as the head stay was extended through the chain locker and secured to the stem as the foredeck may not have been designed for the extra headstay. In addition, running backstays were installed to provide extra support for the mast. By adding a downhaul to the head of the jib, the sail can be raised and lowered from the cockpit. Presuming, of course, the skipper had rigged the sail before the wind hit.

As Sailingharmonie said, who wants to be testing their weather gear">foul weather gear in 40 knots of wind.

[shrspeedblade]

While my boat came with a moveable inner forestay and storm jib, I had only used it once on about a 20kt day "just to see". Later, on a day I really could have used it (just another day sail) I had no interest in going forward to rig the inner stay, lug the storm jib on deck and get it hanked on, run the jib sheets back, and get it hoisted. I was singlehanding, didn't have the jack lines run at that point, and was able to get along ok with 2 reefs in the main and only about 10% of the genoa rolled out.

This inspired me to get a jib bag made (my last boat was hank on headsails and I loved the one it had) so now when I'm heading out for a longer sail or even suspect I may encounter winds over 30 kts I'll keep the storm jib hanked on to the baby stay so at least all I have to do is pull the bag off and run the sheets back. This way I'm safer on deck and also far more likely to use the storm jib when I need it.

I'm not sure how one can be "too small" when you read about veteran sailors in heavy weather running just enough sail to be bath towel size to maintain steerage, which is what you really want running or forereaching.

[Don C L]

I don't know your boat, but if it were me I'd be going over the options with the sailmaker in terms what is needed as conditions change and then develop a plan for that, with your particular boat in mind. In other words, when will you switch from sailing to being hove to? And how will you rig it? A removeable staysail? And beyond that will you run with a drogue or lay to a parachute sea anchor?
The books "Storm Tactics" by the Pardeys and "Heavy Weather Sailing" by Adlard Coles are good resources.

I am not in the market for a storm jib, but in my own case I'd be using one for running, with the main furled tightly, to keep the bow from coming up; not much airfoil needed. But that's just me with my particular boat. And as shrspeedblade says, I'd have it on the bow in a bag already. My boat also came with a trysail which I have heard and read is better for balancing the boat and heaving to but I haven't tried it yet.

[TeddyDiver]

Originally Posted by shrspeedblade

snip..
I'm not sure how one can be "too small" when you read about veteran sailors in heavy weather running just enough sail to be bath towel size to maintain steerage, which is what you really want running or forereaching.

Excactly the point! It's only the other way around, storm jib can be too big.

[donradcliffe]

I'd go with the sailmaker, but agree with the comments about it will never be used. I had a storm jib that came with the boat, and it sat in the forepeak around the world in wind up to 60 knots. It is far easier and safer to just roll up the furling jib most of the way. My only panned use for it was if the primary headsail or foil failed at sea.

[catsketcher]

This from the document

NOR submission 04-08 proposed substantial reductions in maximum areas for S&HW sails for all boats (storm trysail from 17.5% to 12%, storm jib from 5% to 3.5% and reduction of heavy weather jib from 13.5 to 10% of foretriangle height squared, and with luff no longer than ¾ of foretriangle height). The NOR proposals were based essentially on a consideration of wind
pressure/sail area.

A significant body of opinion largely based on practical experience including
that quoted in IRC submission 10-09 did not agree with the Norwegian
proposals. In the analyses of the Hobart Race in 1998 when storm force winds were present there was no resulting recommendation either for or against an overall reduction in storm sail size.

[catsketcher]

I have a storm jib of 6.2 square metres. My fore triangle height is 12.1 metres. This gives me 151 metres squared. This puts my storm jib at 4% of the foretriangle height squared.

Until I just did the calculation, I thought my storm jib was a big one, but it obviously is not. WE have a cutter rig and use the storm jib to go to windward in anything over 20 knots when cruising. I am looking for a bigger heavy weather jib as well, to take us from about 17 knots to 25 and then to use the storm jib after that.

I really like having a storm jib on our inner forestay - it is such a secure feeling being able to get that thing up when the wind gets worrying.

As for the OP's issue, I would say it depends. If you are like me and don't like sailing at all with a rolled up genoa upwind, then maybe a slightly larger storm jib is required. I find a 4% storm jib useful on our boat already buit would like it to be bigger for more regular use.

When I was in the maximum wind my boat has even been in I was running before the breeze (gusts of 45 knots on shore for a few hours) and I just unrolled a scrap of headsail. I liked that even better than the storm jib as I could pull it in and out as necessary going dead downwind, but if I had to head up then the storm jib would have been essential for me. I would be interested in how the Jeanneau 43 rigs the storm jib. Is it on an inner forestay where it can be hanked on and left, or is it going to be wrap around the furler? An inner forestay and storm jib go well together on a cruising boat.

[El Pinguino]

My 39ft Westerly Sealord came with a 150 sq ft ( 14 sq metres) storm jib. I found out the hard way in Bass Strait that it was way too big. Spoke to my sailmaker - he said that would be a 'pre Fastnet' storm jib and a 100 sq ft ( 9.3 sq metre) one would be better.

Found that was still too big - spoke to a sailmaker in Wellington NZ and he said that for Cook Strait and NZ conditions 50 sq ft ( 4.7 sq metre) would be recommended. So now I have three.

The smallest one is ideal down wind in a blow - most often by itself, the 100 sq footer gets a minority of the work. The big one gets a bit of use poled out in conjunction with the working jib - never in heavy conditions.

I'd go with the sailmaker's recommendation.

Extra bit. I really don't like using just a scrap of furled genoa.... centre of effort is way too far frd and far too high - this at the same time as the centre of effort of a deep reefed main has moved lower and closer to midships.