Cutter vs Solent Rig

[model 10]

[QUOTE=a64pilot;.
I theorize that aerodynamically the two of them form a slot, like is on the leading edge of some aircraft.




Like my Stinson? With that, it's not to provide more lift but to control airflow over the aileron. When people block it off, the plane goes faster. However during slow flight, it has a little better control with the slot open.

[a64pilot]

actually a slot or slats keep the airflow attached to the upper surface of the wing and allow for a much higher angle of attack before a stall occurs. Your Stinson if it’s like the 108 has a partial slot, and yes it’s there to keep the ailerons effective at low speeds by keeping the airflow attached over them.
My Maule was the early M-6, which had the drooped tips and smaller ailerons, with the IO-540 and at light weight you could hold at high power an airspeed that the airspeed indicator didn’t work anymore and the ailerons had completely lost effectiveness, you could move them side to side to no effect, when you go that slow you had to use your feet to raise a wing, or of course don’t fly that slow. I put VG’s on the wing to help with that, but the STC required them to be full span, but just in front of the ailerons would have done the same thing your partial slots do.
Later model M-6’s had Hornier tips and larger ailerons that were more effective at low speeds.
Yes at lower angles of attack, say cruise for instance there is more drag, that is where the more complex slats come into play, the retract often automatically and reduce drag, and extend when needed.
The German ME-109 had slats, and could actually out turn the Spitfire because of them, so they are nothing new, good effective old fashioned aerodynamics.
However just based on the way my boat seems to perform when going to windward with both the staysail and Genoa out, I believe the airflow between the two increases lift on the Genoa, I think a slot is formed.
There seems to be an increase in performance beyond what the little staysail should give by itself.

Of course I could be wrong, it’s happened before

[model 10]

I'm puzzled by the leading edge of a head sail. We seem to want as thin a leading edge as you can get, like a supersonic jet (F-104.) Super slow planes have really fat leading edges.

[chouliha]

Originally Posted by SteveSadler

Having delivered boats of both rigs, the Solent stay has a big advantage of not having to change headsails when going to weather in strong wind. Rolling up the 135 and setting the 100 is easy and will point well. But 95% of the time they are just in the way and tacking is a lot of work. If it’s removable where do you store it? I think perhaps just a removable stay and hank on sail may be the best compromise

Thats what we have been doing for the past 25 years. Installed a Solent stay about 15" aft of the headstay. Its detachable and is run aft to the stb fwd shroud where its attached to a ring on the bottom toggle. The Wichard adjuster is then clipped to a padeye on deck. Very simple to connect and disconnect. No backstays as its so close to the mast head

We use this setup for our trade wind sailing. Hanking on the 125 on the solent and with two poles we have a nice wing on wing. We also have a 60% and a storm jib with hanks.

Its proved itself with years of use.

If I was starting over I would use a dynema stay. Lighter and easier to handle. But the hanks must be new.

Safe sailing

Chuck
Jacaranda

[CassidyNZ]

Originally Posted by a64pilot

Why wouldn’t a Cutter’s stay sail be acceptable as a storm job if it was heavy enough cloth?

Storm jobs made to satisfy Cat 1 requirement in NZ is probably twice the cloth weight of my heavy weather jib which is twice the weight of my 135% genoa.

The other requirement for Cat 1 is that the storm jib must be hanked on, cannot be in a track. So that would exclude most cutter rigs as they would most likely be a track-mounted sail on a furler.

Oh, and it has to be dayglo orange. And none of this is negotiable.

So maybe for vessels not based in NZ and not planning on voyaging out of sight if land, one could perhaps double up a staysail as a storm jib. But I can’t.

But for the sake of discussion, I would think that the second jib (is it a staysail?) is likely to be 100% so it would take a stout heart to fly that in a storm at sea. I think my storm jib is probably 30%? I could almost fly it off my flag halyard

[Tillsbury]

What you can do for Cat1 though is have a storm jib permanently attached to a dyneema line, which you haul up with the staysail halyard and attach to the same point as the furler attaches. So you can get around it, and yet stay with a cutter/slutter on a furler.

[jmh2002]

I'm going to stay away from using Cutter or Solent terminology, but here is my ideal setup:

- 2 headsails on the bow
- 1 a code zero type for light air upwind and as well as off the wind
- 1 a 100% blade headsail as a heavier working jib for upwind and all round use in trade winds and above.

The separation between these sails can be boat dependant with one behind the other or one on a bowsprit, etc.

It doesn't really matter too much because it's only inconvenient when sailing with the code zero upwind in light air. Then the code zero will need to be furled before tacking (as even IMOCA and Volvo race boats do) but this is not really a big problem unless also short tacking up a coastline or channel or something. In this case put up with it or use the 100% blade instead. Most cruising boats don't do a lot of short tacking for extended periods.

Additionally I would then have another inner stay set much further back. In general this would only be to set a proper heavy storm jib for offshore sailing, although some type of staysail could also be set here if so desired on long legs (or for more enthusiastic sailors).

The storm job and staysail can be hanked on. Even on a 50ft boat the storm jib is small and easily managed by hand. Hanked on, but bagged and lashed on the centerline before going offshore. Simple and not a lot to go wrong when it matters, and well as bringing the center of effort way back in heavy air.

This inner stay can be removable. These days it doesn't even need to be wire. If running backstays are required for this that's ok too because again this setup would mostly only be used when offshore on a long leg. The runners can even be totally removed from the mast too when coastal or down island.

The 2 headsails on the bow should be roller furling, but not roller reefing. I realise this will not be most sailors preference but the shape of a partly furled headsail is terrible and for going upwind it's worthless.

So instead the headsails should be on modern lightweight 'continuous line furlers' just used to set and douse the sails. No heavy furling rod, no drum to jam and cause problems, longer, lower, and more efficient luff length (especially for the 100% blade), etc, etc.

With 3 different headsail options available I prefer to just swap from the code zero, to the 100% blade, and to the storm jib as the wind increases. The 100% blade will cover quite a wide wind range so it will stay set while the mainsail is reefed, until there is so much wind that storm jib and 3 reefs is sufficient. After that the mainsail can be taken totally down and secured and you already have the storm jib set which is easy to manage even in very high winds.

I have had a setup similar to this in the past and found it to be a very versatile all round rig that enables multiple possibilities for different points of sail and wind strengths, facilitates shorthanded sailing, whilst still retaining a bullet proof simple setup for offshore passages.

My 2 cents

[a64pilot]

Originally Posted by CassidyNZ

But for the sake of discussion, I would think that the second jib (is it a staysail?) is likely to be 100% so it would take a stout heart to fly that in a storm at sea. I think my storm jib is probably 30%? I could almost fly it off my flag halyard

I’d just as a guess, guess that my Staysail is about 50%, but that is just a WAG.
This has a decent picture, but I Don’t think has dimensions of the Staysail. However of course being roller furling it’s easily reefed to smaller, I believe mine is 11 oz cloth, but don’t remember. I did have it made from heavier cloth than normal as it’s my Storm sail, I don’t have a dedicated Storm sail.
https://sailboatdata.com/sailboat/island-packet-38
It’s not yanked on, nor is it day glow orange.
I understand the requirement to be orange, but the yanked on confuses me, I assume it’s because it’s a Storm sail only and yanked on is easier than roller furling to change sails?

[jmh2002]

Originally Posted by a64pilot

I understand the requirement to be orange, but the yanked on confuses me, I assume it’s because it’s a Storm sail only and yanked on is easier than roller furling to change sails?

And because roller furling can be unreliable, especially in storm conditions.
Whereas with hanked on there isn't much to go wrong. Plus as I mentioned in my post above, a real storm jib for most of the cruising boats here (sub 50ft) is very small and easy to manage by hand.

I wouldn't have it on a furler. Also because it will probably only be used on offshore passages it can be removed and stowed for the rest of the season.

Storm trysails used to perform the same function for the mainsail. A very basic heavy sail, no battens, separate track, boomless, etc, to try and eliminate any failures points that the mainsail might have.

[Markhunter1097]

Now with the new cable less code zeros and jibs, running a Solent or cutter rig is easy so long as you have the attachment points

[jmh2002]

It's difficult to tell from looking quickly but I'm guessing that a real storm jib for your boat would be about 50% of the size of your staysail.

Not sure how that would work with the boomed setup, but I expect that it could be flown in the empty triangle above the boom (when the staysail is furled or lowered).

[a64pilot]

Originally Posted by Ecos

I'm puzzled by the leading edge of a head sail. We seem to want as thin a leading edge as you can get, like a supersonic jet (F-104.) Super slow planes have really fat leading edges.

Our sails are single surface airfoils. For an example of that look at most ultralights, it works, but not nearly as well as double surface.
WWI aircraft were all very thin airfoils and many had horrible handling, it’s amazing that they could be flown. It wasn’t until the monoplane became common that the discovery of a thicker airfoil worked better and gave the advantage of being able to hold landing gear and fuel tanks etc. Originally they were thicker due to strength considerations, thin airfoils required external bracing. They learned by trial that thicker internally braced airfoils were less drag and faster than thin externally braced airfoils.
The real thick airfoils are largely to give good low speed handling and stall qualities, they allow high angles of attack etc.

I believe some racing boats are at least partial double surface airfoils?
Having even a partial bottom surface, say the front 20% or so gives most of the advantages of a double surface.

[jmh2002]

Here is some regulatory info, even if it is from the ocean racing point of view (so cruising should be even more conservative?):

Storm Sails 101
Before you have storm sails made for your boat, read the ISAF Offshore Special Regulations for Storm and Heavy Weather Sails.

They are written for ocean racers but contain some sensible recommendations, not least among them a suggestion that storm sails should be built in a dayglo color.

Note that ISAF bans the use of high-tech fibers in storm sails. Other points:

• Storm jibs must have an alternate means of attachment to the stay, other than the luff groove

• A trysail should have an area no greater than 17.5 percent of mainsail luff length x boom length (P x E) and should be capable of being sheeted independently of the boom

• A storm jib’s area must not exceed 5 percent of foretriangle height squared, and its luff must not exceed 65 percent of forestay length

• A heavy weather jib or (stay)sail should be no larger than 13.5 percent of foretriangle height squared

• If using a reefed mainsail in lieu of a trysail, the luff must be reduced by at least 40 percent

[jmh2002]

Originally Posted by jmh2002

• A storm jib’s area must not exceed 5 percent of foretriangle height squared, and its luff must not exceed 65 percent of forestay length

• A heavy weather jib or (stay)sail should be no larger than 13.5 percent of foretriangle height squared

As an example:

@a64pilot, if I have the data and calculations correct for your boat (from your link: https://sailboatdata.com/sailboat/island-packet-38)

Foretrangle height (I) = 46.5ft

Storm Jib: 46.5 x 46.5 = 2162.25 x 5% = 108 sq ft

Heavy Weather Jib/Staysail: 46.5 x 46.5 = 2162.25 x 13.5% = 291 sq ft

SailboatData lists your total Foresail area as 414 sq ft, so the numbers seem in the right range, with the storm jib calculation coming out to around 25% of the total Foresail area (and my earlier guess being that 50% of your Staysail size would look about right).

Also note that these are recommended maximums.

I guess this would also make your Storm Jib only a 3 or 4 ft long on the foot, so quite manageable by hand, and as a hanked on sail (or a free flying sail with a synthetic luff wire).

[a64pilot]

Thanks but as in truth we aren’t likely to hopefully need a true Tri sail. I’ll stick with what we have. We have a boom furling main, so of course we can reef it down as small as you want.
Thanks for the calculations though.