The old adagio holds true once again :

Each should order and sail with a mainsail that is cut for your crewweight and way of usage/skill. That will be the fastest sail for you.

Wouter

Does the need for a custom sail due to weight on the F16 mean one HAS to have 2 different mains depending on 1up or 2up? It would seem so, or is the jib (or lack thereof) enough to make up for the extra weight of the crew.
I am sure this has been mentioned somewhere but I am too lazy to find it.

No

Most of us, and I'm personally included in that, have only one mainsail that we use in both singlehanding and doublehanding. I'm doing equally well in both modes when compared directly to the F18's in my club races.

It is, however, strongly adviced to have your mainsail cut (optimized) for your crewweight AND/OR dominant usage. This will get some extra performance out of YOU sailing the F16 compared to having the standard sail and YOU NOT being at the design weight for the standard sail. Of course if you are close the optimal weight for the standard sail then THAT sail is just perfect for you. You must also remember that you can often have the sail cut for your weight for either no extra charge or very little extra charge. Cost therefor is no reason to not do it.

For really active racers or sailors looking to spend some extra money on their boat the option of having two mainsails is an attractive one. This is not because it is needed but because it is the best upgrade for the amount of invested money. And we are ONLY talking about the mainsail here and when you are often doing singlehanding racing in addition to doublehanding. It is all about getting the last few % of performance out of the singlehanded setup. To understand this fully you need to know a few things.



-1- It is possible to tune down a competitive doublehanded mainsail for good singlehanded use. This works relatively well. A good doublehanded mainsail is always cut a little fuller and you can always make a sail flatter by pulling on the controls.

-2- It is NOT possible to tune up a competitive singlehander mainsail for good doublehanded use. A good singlehanded mainsail is cut relatively flat and it is not possible to make it fuller by pulling on the controls.

-3- Because of -1- and -2- the standard F16 mainsails are cut for optimized Doublehanded use at about 135kg-140kg and custom mainsails are as good as always cut for DOUBLEHANDED use at the specified (personal) doublehanded crew weight

-4- A doublehanded mainsail is positioned behind a jib and the cut of such a mainsail is a little different in the bottom halve. Is is flatter here then a typical singlehander mainsail. On F16's the mainsheet system and outhaul system allows a singlehanded sailor to largely correct this when using a doublehanded mainsail for singlehanded use, but it is never a perfect compensation.

-5- Tuning down a doublehanded mainsail for singlehanded use requires some additional skill then just hoisting a specialized singlehander sail. See point -4- you need to know this stuff and how much readjustment is needed for competitive racing.



These points above lead to a situation where nearly everybody who uses only one mainsail has it fully optimized for sloop rigged doublehanded racing at their combined crewweight. And that is okay, because being competitive when sailing singlehanded requires first and foremost a considerable amount of skill and experience so the cut of the sail will not hold you back much in the beginning. This is true for all singlehander designs out there. But when you move up the learning curve and become more competitive you'll find that using a doublehanded optimized mainsail will require more and more careful sheeting then a specialized singlehander mainsail. At the more competitive end of the spectrum this becomes more of a disadvantage, in addition it may be more tiring. You need to work harder to get the same performance. Here enters the attractiveness of a second mainsail, one that is fully optimized for singlehanded use (and that can only be used for that). For doublehanded racing the old main is used while this specialized singlehander mainsail used in solo racing will be easier to achieve maximum performance with, less tiring and in some cases even more smooth/more easy in its feel. In the really high end of the fleet these small differences can make the difference between being first, second or third. Further down the fleet these same difference often don't affect the final positions at all. Only rather skilled singlehanded sailors will be able to notice the differences, so for most of us the one mainsail, one cut for our personal doublehanded weight, is enough.




The jib is by far the biggest factor in making up for the extra crew weight. In addition to this; the mainsail needs to be fuller as well. But I refer to points -1- and -2-. The best approach is to have a fully optimized doublehanded suit of sails and tune the mainsail down for singlehanded usage. This works quite well and by far most of us F16's are applying this technique with succes.

Never forget that we are talking small gains here, nothing really major.

I hope this explains things.

Wouter

I talked with Matt some about the cut of the sails when I ordered the Blade. We came to the same conclusions stated above. Get the most powerful sail plan available and make sure you know how to depower (some of this depowering will HAVE to take place on the beach prior to rigging - prebend). A lot of my singlehanding will come in light air conditions, so a fully powered rig works for me. My problems will come when tyring to learn how much prebend and rake to put on prior to heavy air singlehanding. I guess it is all a little trial and error.

I'd feel a little better about dictating sail cut on the next set of sails - after I have some experience on the boat. In the meantime, I will defer to Matt and Ullman Sails (Matt's builder of choice).

BTW, delivery is confirmed for mid-March. Gulfport is still a possibility for me.

This certainly has me thinking that I may want to have sails made for me instead of the stock cut with my Blade. I'm back to excercising after a 3 month hiatus last year and should be around 136-138 by summer (139.5 today). I'm certainly a light-weight when solo and even with a 130 pound crew, somewhat a light dual. I'm also questioning if I should just get 2 mains while I'm at it. If I went with 2, would I just have a uni and sloop (same size) or would I make the uni slightly smaller so I could handle stronger winds? Then I could even use the smaller uni in sloop rig when it's really blowing. Typically will be sailing in 6 to 22 knots. Less than 6, I'd rather sit on the beach with a beer. More than 22-25, my wife would rather sit on the beach watching me drink a beer.

Without going into details :

When going for one mainsail only then have it custom made for 140 + 130 lbs = 270 lbs (122 kg); as stated earlier it should be possible to have this done for no additional cost or at the most a very small amount.

When going for two mainsails then have both mainsails the same size (area) and just have the sailmaker alter the sail cut and luff round. Area is not much of a concern; i.e. it won't help you much at all to get a smaller sail. By far the biggest gains are made by changing cut and luff round.

Don't think you can really use the singlehanded mainsail for heavy wind doublehanded usage in any competitive way. In addition depowering the F16 rig for heavy winds is quite easy and far reaching. Don't worry to much, just learn the tricks and you'll be fine.

The depower tricks themselfs are really easy. Derotate the mast and pull simulatiously the downhaul and mainsheet really tight. And I do mean REALLY tight. This will make the sail really flat and have the top of the mast bend of considerably. The last looks scary but the mast can take ALOT of flexing so down worry about it. These tricks will calm the boat right down.

I should add here that having two mains is a benefit but not really necessary. Having the mainsail cut for your expected doublehanded weight is however strongly adviced. This will make you fastest and will make you competitive again all other F16 crews and go a long way in make singlehanding more manageable. There are no bad sides to that approach.

Wouter

Wouter,

Considering the AHPC mast and my weight, how much prebend should be cut into the sail? I read that you are using 20mm prebend. Does that mean you should have 20mm prebend cut into the sail to match the mast? This is my assumption that ideally the two match, but this assumption may be wrong.

Let the sailmaker worry about the right amount of luff curve and prebend of the mast. In principle is the luff curve always more then the prebend ad you want a flat sail (when layed down on the floor) to be a curved wingsection when it is flown on your mast. To force the flat (two dimensioanal) sail into this 3 dimensional shape you need a difference between the sails luff curve and the bending of the mast. You just don't want to much of it, depending on conditions and crewweight so you reduce this difference by prebending the mast. There are some more complex working added to this as well but thwn we'll go too much into detail. If you are interested in that then try to get a book on saildesign and read it. It will be far too much for me to type it all up. It is also a subject that is best learned and understood when you are actually seeing its effects on your boat happening. So my basic advice is to have the sailmaker do the design work of the sail for you after you have just specified you intend crewweight, usage and dominant sailing conditions.

Those 20 mm I'm running was a experiment after I had a sailmaker design and build me a mainsail. I think however that I'm running a different prebend right now, one that suits my way of sailing and conditions better. I can't remember how much I'm using right now, but I can look it up in my trim and tuning booklet.

Wouter

I'll jump in here even if you adressed Wouter..


Pre-bend is how much the mast has been bent out of column by sweeping the spreaders aft and pulling tension on the diamond wires.
The sail have luff curve cut into it, not pre-bend

To determine the amount of luff curve, you ned to consider several other factors as well as pre-bend. Your sailmaker uses luff curve to put depth into your mainsail. If you put your main on a flat surface you will notice that it lies mostly flat. But when you hoist it on your mast it has draft. The reason is that the luff curve is quite a bit more rounded than your pre-bend, so the extra cloth 'transforms' into draft.
To determine luff-curve, your sailmaker not only needs to know how much pre-bend you use, but also how stiff your mast is and what bending properties it has. Your bodyweight and average sailing conditions also goes into the equation. When your sailmaker have a good knowlegde of all this, he will design your luff curve according to all these factors including how much draft you will need. He will rarely get it right the first time he builds a sail for a new type of boat/mast, hence it's a good idea to use sailmakers with experience on the specific masts/boats.
To further complicate the matter, you should tune mast pre-bend to your body weight and mast stiffness (no two alu masts are alike) and have the luff curve cut accordingly. Only then is your mast pre-bend and luff curve matched and your power-plant able to give you 100%. While the Tornado had alu masts olympic crews was constantly looking for masts with optimum bending characteristica for their style and crew weight. Usually they lugged around two or three extra masts on their trailing rigs, and breaking their favourite masts was a minor disaster.
Consider the last point as trivia unless you are on an olympic/worlds skill level.

If you want to look at this for yourself it's an eye opener to bring a digital camera along and hoist your main. Sheet it in a bit and take a picture from 10-15 meters away abeam of the boat. Then sheet the main max, max the downhaul and do another picture. Go home and put the two over each other in photoshop/gimp and look at how the mast curve/bend have changed. Rotating the mast will change the bending properties further. This is a fun exercise, enjoy