Sizing a staysail / heavy upwind jib

[Minerva]

I'm planning to keep our boat afloat this winter for the first time and hope to get some winter sailing in*. We are also planning on sailing to the Azores next summer.

On our Moody 34 we have a news/one season old, 135% padded luff Genoa that sets great, but will be taken down and safely stowed for winter. We also have an emergency forestay that sets about a foot aft of the drum.

I'm thinking applying man maths to justify the need for a new (or ideally second hand little used) hank on sail; thinking a heavy upwind jib with high clew / staysail.

Question being what sort of % luff / foot measurement ought I be looking out for?

*I fully appreciate that any winter sailing I do this winter will preferably be when there is a great big fat high pressure with very little wind!

 

[B27]

I'd be looking for a blade jib which nearly filled the foretriangle and lived on the furler.

A staysail for use when it's too windy and the genoa is rolled up is a different animal from an all-round sail for the Winter.

For used sails, I'd consider anything with a significantly shorter foot than the current genoa, ideally fairly high aspect but see what bargains are out there.

The days you sail in the winter won't be the gales. Unless you're doing racing or heavy weather training or similar, you will pick the nicer days and avoid anything silly, so the equivalent of 1st reef is probably as small as I'd want to go.

 

[RunAgroundHard]

To overcome the lighter wind area, consider having a working jib style but with a reef in it: higher second tack and clew sewn in. Make the sail a bit heavier. Allows better lighter wind area, as well as stronger wind area.

I have a similar set up, but permanent inner forestay. I roller reef my genoa, with foam luff, and use my staysail (shaped like a blade). I then roll away the furling genoa and just use the staysail.

My point is, maybe keeping your furling genoa on is not so bad, then roll away fully, set your inner stay and hoist your working jib / blade sail. If you don’t want that, then first paragraph is a better solution for a winter sail.

You could also buy a smaller furling sail and use that in the luff groove and furl it. That would be a good compromise.

Sailmaker can advise on best size. Basic jib area calculation is ((I x J) / 2 x LP) x0.85 for smaller working jib, x0.95 for larger.

 

[Minerva]

To overcome the lighter wind area, consider having a working jib style but with a reef in it: higher second tack and clew sewn in. Make the sail a bit heavier. Allows better lighter wind area, as well as stronger wind area.

I have a similar set up, but permanent inner forestay. I roller reef my genoa, with foam luff, and use my staysail (shaped like a blade). I then roll away the furling genoa and just use the staysail.

My point is, maybe keeping your furling genoa on is not so bad, then roll away fully, set your inner stay and hoist your working jib / blade sail. If you don’t want that, then first paragraph is a better solution for a winter sail.

You could also buy a smaller furling sail and use that in the luff groove and furl it. That would be a good compromise.

Sailmaker can advise on best size. Basic jib area calculation is ((I x J) / 2 x LP) x0.85 for smaller working jib, x0.95 for larger.

Thanks - thats loosely my plan, over winter obviously the new roller genny will be safely stowed away from any risk of storm damage. Who knows, ff the staysail setup works, I may even look to install a second furler in due course too.

 

[fredrussell]

Thanks - thats loosely my plan, over winter obviously the new roller genny will be safely stowed away from any risk of storm damage. Who knows, ff the staysail setup works, I may even look to install a second furler in due course too.

I’d leave the genny on. I sail year round UK and there plenty of fine weather but light winds days in the winter period when a 135% headsail is just the job.

 

[SaltyC]

I too sail all year, when I got my new (to me) boat I had a replacement 135% genoa and an original 115%, the boat was under powered with theorigianl. It turned out the 115% didn't have a UV strip and the foot and leach were 'rotten'

I had the sailmaker cut it down (remove damaged cloth) to circa 100% a Brilliant winter sail!! due to removal of 400mm(ish) of foot and leach she is quite flat and good i the denser and heavier airs.

Perhaps a smaller jib should be considered? at what wind strength do you reef the 135%? I was at 14 knots. So West Coast I was reefed with consequent poor shape the majority of the time.

Now have a new 115% Jib but still use the old 100% in winter.

 

[dunedin]

To overcome the lighter wind area, consider having a working jib style but with a reef in it: higher second tack and clew sewn in. Make the sail a bit heavier. Allows better lighter wind area, as well as stronger wind area.

I have a similar set up, but permanent inner forestay. I roller reef my genoa, with foam luff, and use my staysail (shaped like a blade). I then roll away the furling genoa and just use the staysail.

My point is, maybe keeping your furling genoa on is not so bad, then roll away fully, set your inner stay and hoist your working jib / blade sail. If you don’t want that, then first paragraph is a better solution for a winter sail.

You could also buy a smaller furling sail and use that in the luff groove and furl it. That would be a good compromise.

Sailmaker can advise on best size. Basic jib area calculation is ((I x J) / 2 x LP) x0.85 for smaller working jib, x0.95 for larger.

Spot on - as tall and narrow as you can fit on the furler.
I did something very similar, buying a “winter jib” so that the expensive North jib with vertical battens doesn’t need to stay on all year round.
Your choices will be limited so see what is available. One thing I found was that there are different sizes of luff bolt rope to suit different makes of foil. Make sure you know your size or it won’t fit without modification.

 

[Martin_J]

Minerva...

You said in the original post that you were thinking of applying the maths..

I know you're not racing but after doing a few Fastnet races in my Moody and had to comply, I have always looked at the Offshore Special Regulations when hit with a question like this.

You will find a very clear difference in size between the 'heavy weather jib' that you are asking about (to save the furling genoa) and a 'storm jib'..


https://www.sailing.org/tools/documents/WSOffshoreSpecialRegulations20222023v2-[27823].pdf



I have done the maths (and measurements) and both our heavy weather jib and our orange storm jib fit those percentages exactly. Both were required for Cat 2 offshore races.

 

[Fr J Hackett]

If you are thinking about putting a sail on your "emergency forestay" depending on where it's attached to the mast you should think about runners.

 

[Martin_J]

Maybe I should have included the link to all the Offshore Special Regulations i.e. Different categories for each different distance from shore.

It's useful reading for any trip to the Azores...

https://www.sailing.org/inside-world-sailing/rules-regulations/offshore-special-regulations/

 

[Minerva]

Minerva...

You said in the original post that you were thinking of applying the maths..

I know you're not racing but after doing a few Fastnet races in my Moody and had to comply, I have always looked at the Offshore Special Regulations when hit with a question like this.

You will find a very clear difference in size between the 'heavy weather jib' that you are asking about (to save the furling genoa) and a 'storm jib'..


https://www.sailing.org/tools/documents/WSOffshoreSpecialRegulations20222023v2-[27823].pdf

View attachment 181567

I have done the maths (and measurements) and both our heavy weather jib and our orange storm jib fit those percentages exactly. Both were required for Cat 2 offshore races.

That’s really useful, thank you.

Interestingly it’s suggesting that for a ~12m forestay (I?) then I should be looking at just under 3m^2 heavy weather jib with the storm jib even smaller still. That feels pretty small

I’ll print off the regs and swot up; probably a very wise base to set as a benchmark.

 

[Martin_J]

And I have just re-read that extract in my screenshot. It defines how to work out the sail area for a post 2011 sail.

 

[Minerva]

If you are thinking about putting a sail on your "emergency forestay" depending on where it's attached to the mast you should think about runners.

Very wise of course to check - the upper attachment is about a foot (if that) below the actual forestry attachment - designed not to need a pair of runners.

 

[B27]

'Heavy Weather' means anything from surviving a named storm, down to the fat boys enjoying a blast on their Lasers.

We should separate talk of storm jibs and all that, from considering a smaller jib optimised for all-round winter sailing.

Sailing on the shorter days of Winter, we need to make progress, so too small a sail can be a mistake.

 

[Supertramp]

I have a hank on jib cut with a high clew and about half the area of the roller genoa. My boat is 36ft. It's a really useful sail in 20knts+. I have carried it in 30knts with gusts beyond. While a furler would be good it's not essential and I like the simplicity of hank on. My foredeck is wide and protected by bulwark so sail handling is manageable.

I just acquired a storm jib off a larger yacht which gives me another hank on sail sized between my current Solent jib and my storm jib. Not had to try it yet. Might seem like overkill but I find having the right sized sail makes for much less stressful sailing in windy conditions.

When I sail through the winter I leave the furling genoa on but secure it with a tie so it can't unfurl. I agree with others though - you will probably have great, if cold, sailing without the need for storm sails.

 

[Tranona]

Very wise of course to check - the upper attachment is about a foot (if that) below the actual forestry attachment - designed not to need a pair of runners.

That is exactly what I am doing at the moment with a mast head rig so that I can have a working jib (around 90% and higher cut) on a furler and on the outer forestay a 135% genoa for use in light airs and offwind. The large overlapping genoas are in my view a PITA for normal cruising as the primary foresail. They do not improve windward performance and are hard work to handle, particularly tacking and often need 2 or 3 rolls to work well in anything other than very light airs.

In your position I would look to getting a blade type jib made for the current furler for all round use in the winter and see how it performs. and then consider making the inner forestay permanent with a furler and put the genoa on the outer. The type of "slutter" rig is popular on some bluewater boats

 

[B27]

...... The large overlapping genoas ........................ do not improve windward performance ....

I think large numbers of people who've raced would laugh at that.

No substitute for sail area.

 

[Frank Holden]

That’s really useful, thank you.

Interestingly it’s suggesting that for a ~12m forestay (I?) then I should be looking at just under 3m^2 heavy weather jib with the storm jib even smaller still. That feels pretty small

I’ll print off the regs and swot up; probably a very wise base to set as a benchmark.

What I have - Westerly Sealord 39 foot nominal 8 tonne boat.
Since buying a new furling genoa in 2014 I have only bent it on once - for the long downwind run from Puerto Montt to Ecuador.
The rest of the time I just use my working jib (100%).
For storm jibs. The boat came with a 150 sq ft storm jib which was found to be way too big. My sailmaker said that was a 'pre Fastnet' storm jib and fitted me out with a 100 sq footer. Crossing the Tasman to NZ I found that was also too big. Sailmaker in Wellington said that around Cook Strait they would suggest 50 sq foot ( about 5m^2 ) so I now have that as well.

That seems about right. On passage I typically have both the 50 and 100 hanked on ready to go. Sometimes I hoist the 100 and sail her as a cutter.

 

[srm]

I'm planning to keep our boat afloat this winter for the first time and hope to get some winter sailing in*. We are also planning on sailing to the Azores next summer.

On our Moody 34 we have a news/one season old, 135% padded luff Genoa that sets great, but will be taken down and safely stowed for winter. We also have an emergency forestay that sets about a foot aft of the drum.

I'm thinking applying man maths to justify the need for a new (or ideally second hand little used) hank on sail; thinking a heavy upwind jib with high clew / staysail.

Question being what sort of % luff / foot measurement ought I be looking out for?

*I fully appreciate that any winter sailing I do this winter will preferably be when there is a great big fat high pressure with very little wind!

I used to keep my boat afloat all year round in Stromness marina, Orkney. Winter depressions could give sustained blows of around 85 knots for the best part of a day. I normally left the headsails on and would manage at least one day sail around Christmas/New Year plus a number of trips out as we had the sheltered waters of Scapa Flow to play in. I only took the headsails off if leaving the islands for longer than a few days, or if a serious blow was forecast.

Never thought about needing "winter sails", but my last two boats were cutter rigged with a high clew to the headsail that kept a good shape even with a deep reef. Also I always had the staysail. I can see your ideas as being sensible though for an ocean passage as a back up in case the genoa gets damaged or for strong winds. You could also use the second headsail when on a run poled out wing and wing.

 

[Chiara’s slave]

I think large numbers of people who've raced would laugh at that.

No substitute for sail area.

If you race, you’re going to trim the sail, and reef it much later. Cruisers just don’t tend to set their overlappers well, and whatever the cut, and foam luff or not, they just don’t have the shape when heavily reefed. A 100% blade jib on the same furler can still be flat when half rolled. So you’re both right, IMHO. Racers just want the max area, but cruisers are often better off compromising.