I know a few of you out there are fine-tuning and trimming your way to better singlehanded speed as well, So here I will give a summary of what seemed to work for my last sunday.

Platform = Taipan F16 (full F16 width, entlarged square-top head 580 mm on my F16 sized mainsail)
My weight = 83 kg (on a good day)
Mainsail was made by Redhead sails Australia
prebend = 20 mm
spreader rake = 50 mm with 390 mm long spreader arms.
Top 2 battens were of the stiff kind, 3rd from the top and down are medium battens

Conditions between 15 and 22 knots. severe chop and short waves right rather close to another.

I was sailing with too much mast rake as I have the boat setup for doublehanded racing. Even for doublehanding I think that I can reduce the mast rake.

What eventually worked for me on the upwind leg was :

LOTS of downhaul and very little mastrotation. Rumour has it that Redhead sails like lots of downhaul, more so than Ashby and Goodall sails.

When it was blow about 18 to 20 knots. I set the mast rotation so my rotator arm was pointing at the leeward rudderblade and sometimes even less. Yes, you guessed it right, that is indeed very little rotation. Absolutely NO smooth transition between mast and sail but I did go noticeably faster and the boat became alot more controllable as a direct result.

So I set the rotation to this point, than pulled the mainsheet tight and then the downhaul. Then I pulled the foot of the mainsail tight. Then I janked on the mainsheet some more and pulled the last bit out of the 1:12 downhaul. Then I released the mainsheet slightly and headed down for about 5 degrees and went out on the trapeze. Boat felt like she was skimming the water and I hardly ever had to head up in the gusts. The boats stayed very level. A significant difference from before.

The main component seemed to be the downhaul (lots of it); the other factors helped but after pulling the downhaul really tight once more (and heading down a little) the boat just fell into a groove.

Point to take away : In these conditions (when using the superwing mast sectio) forget about the smooth transition between mast and sail. Set the mast rotation sufficiently small to depower the rig in the top and reduce the draft of the sail. Remember flat is fast in these conditions. Then try at least one heaps and heaps of downhaul with a tight mainsail. The mainsail will be tights as a drum and almost as flat as a board but in my case this all seemed to result in a very controllable and fast groove upwind.

Downwind is another matter. But here I really haven't found a magic groove yet.

Wouter

Hi all,

Wouters post makes sense, although I wouldn't neccesarily say that you can have too much rake, especialy in strong winds. On Mossies some one ups use more rake than two up, Altered also carries alot of rake, it's realy about balance, it depends on where your centre boards are, how big they are how big rudders are, where main beam is in relation etc.

Without using to many technical terms my theory is as follows.

Uni rigs generaly don't feel they drive upwind in strong breezes the way a sloop rig does, it's very easy to get what I call the staggers.

The more rake you have the more you get the Sailboard effect of driving the boat through the mast, if it is raked back that means the force in the mast is slightly forward, if your mast is more upright the forces drive more down than forward. Disagree if you like it is just my theory.

The limit to this is as I said earlier the balance of the boat, which is why some cats can not sail cat rigged. On the Mossie and Altered I have always raked the mast back until the weather helm became so great that you where pulling at the tiller all the time to stop it turning into the wind. Then I would try pulling on more downhaul which opens the leech of the main reducing weather helm and also stand further back on the boat so the bows are not digging in, as if the bows are deep in the water this will also try to make the boat turn into the wind. I have even seen some namely Tim on Mossie pull his centre boards partly up, which also reduces weatherhelm. When you have tried all this if you still find yourself pulling at the tiller, assuming before raking mast back, your rudders where light, your rig needs to be more upright.

It has been my experience that you should try and persevere with what may seem at first to be to much rake and try the remedies described above, because the cat rig is much easier to get in the groove and drive upwind in strong winds with rake. But pulling on the tiller to stop it turning into the wind is also slow (rudder blade side on to water flow makes a good hand brake), so balance again is what it is all about.

I think maximum rake is the best set up for cat rigged as I believe you need to optimise the boat for the conditions it is naturaly slowest in, and the most difficult to sail in. This means your performance is more even, than if the boat is set up for what it is already best at, in the case of cat rigs, light wind.

Again the most important point. Each design is different, you realy have to work out what is the maximum rake for your boat, obviously start by looking at other boats but if you want to push it to the limit you have to get the feel for YOUR boat. Example A class cats, designed to be sailed only cat rigged one up, generaly have more rake than cats that are being sailed cat rigged that can be sailed one or two up, cat or sloop rigged, as their centreboards etc. are further back on the boat. Even the shape of the hulls effect it, deep thin bows cause more weatherhelm than newer fat bottom designs.

Hope this makes sense it would have been shorter to use tech talk ie. centre of lateral resistance vs. centre of effort etc but I figure if you know these terms you know the theory. I hope not.

Regards Gary.

The reason why I think that I have too much mast rake is that I'm stalling my rudders when cat rigged, especially when lifting the luff hull. I get rooster tales behind my boat and it feels like it is decellerating. I was already at maximum foot tension and downhaul tension. I partly pulled out the luff from my mast track at one point so I can't never have had too little foot tension.

It feels like the boat is slowed down by overturning the rudders. Besides, I seem to have excellent height which can be an indication that I'm loading up my rudders alot. I will try to rake my mast a little more forward and see what happens. Small incrediments of course !

Wouter

Gary--I just tried raking more this weekend and loved it cat rigged. I resisted before because I always figured why should I rake more cat rigged than sloop--just didn't make sense to me. But I really liked the feel of the boat driving upwind better with a bit more rake. Now I have slight weather helm upwind and slight lee helm with the spinnaker up. Didn't notice less speed downwind. Nice balance over all. In heavier winds, I plan and raking even more.

The top two battens weren't of the stiff kind but of the "Extra stiff" kind the others were "normal" (on my battens normal = stiff). The top 2 battens are therefor just like thick rods and so hardly bend at at. I have this extra set of battens to flatten out my top for solo sailing. That is because :

I have (and sail) with a mainsail that is optimized (cut) for a combined 140 kg crew weight, so in general it is very powerful for singlehanding. It is also optimzed (cut) for sloop sailing so the bottom halve has the draft further back (at about 50 to 55 %) when compared to an optimized singlehanding sail.

Still I felt pretty much in control during those 15 to 20 knots.

But I think I needed alot of downhaul also because I was singlehanding using a sail that is optimized for doublehanded sailing.

Take note of that.

Wouter

Very good point -- the draft in the main is different depending on whether it is a sloop or unirig. I knew that, of course, but I hadn't thought about looking at a sail in terms of it being used in both configurations.

And the main only has to have the draft farther back toward the bottom if you have an overlapping jib; right?

Sorry if I am asking something you have already addressed.

I think you want max draft further aft, and less draft, even with a non-overlapping (selftacking) jib.
If you look closely at a mainsail cut for a sloop, the deepest part will be very high up. This is counterintuitive for many, as it doesn't seem to make sense to have the most powerful part of the sail high up

Credits to you Wouter, many constructive and good posts lately. More sailing and less administration lately?

However, for an "optimized" unirig sail, wouldn't you want the maximum draft to be at a uniform distance back from the mast all the way from top to bottom?

Yes, indeed. That is what we are all hinting at.

Wouter

For a good discussion/explanation, you should read what Andrew Landenberger writes ( Landy's site ), even if it might leave you more confused than you was before you read it

Uniform draft might be fastest under some conditions, but slower at other. For max speed/VMG, you have to trim your mast/sail to the current conditions.

The short answer is yes, in my opinion, a uni-rig sail will have a more uniform draft/position for max draft, since it doesn't have to cope with the bent flow coming off the jib.

OOOHH YES !

In the weekend I have time of and were are in the middle or the racing season.

Today an impromptu club race with some 15 boats if not more. Two heats.

Next sunday, the second part of the Kennemer Cup

Weekend after that Westland cup. 2 days of racing with on two courses with about 80 boats.

Then I think I have a weekend off and then we have the REM race 2005 at my own club. Also a full weekend but now contained two distance races.

I'm not doing much else then working on my assignment and sailing. (and some fiddling with my boat to get things running just right)

Also the class seems to take care of itself. Which I think is great, afterall a class like this must be a group effort and I won't be around forever (and pull each cart that comes along)

I'm having fun !

Wouter

Well, then, what I am hinting at is, if you have an F16 and plan to be racing it sometimes as sloop and sometimes as unirig, is it necessary (or advisable) to have two different mainsails?

In light wind and medium conditions, I would have liked a main cut for cat rig sailing. If you are overpowered, I dont think the difference would be so large?

Well, the next question is, if you are buying an F16 and you are going to be sailing it half the time as a unirig and half the time as a sloop rig, which sail cut would work best for both?

Mary, depends on whether or not you`re Australian .
Just kidding, but my point is that the Auzzies are quite a technical bunch, as you`ve probably read you can get a different mast section for the Taipan for single-handed sailing, and obviously a different cut mainsail to match the more flexible mast, but then you can`t sail sloop with that rig, and it won`t support the spinnaker.
The Australian Mozzie sailors even built different hulls for sloop/uni sailing, the unirig boats had a double forestay and could not fit a jib for sloop sailing, the bridle strop put too much strain on the bows since they were not built to cope with the extra loads.
In answer to your question, probably yes it would be better to have 2 mainsails for the different configurations, but since most of us are weekend sailors who don`t get paid to win races, most of us will get the sloop rig and tune it a bit differently for sailing uni.

Question 1 :




I would say "not necessary"; I think it will only pay off when you are already finishing in the top 3 (or top 5)of decent sized fleets regulary. If one does not then effort is much better spend on sorting out your tactical or trimming mistakes.

About it being advisable, well I can't see that having two specilized sails will hurt, but I really don't see that much in it as well. I doubt wether the extra expense is worth it unless you are getting really serious about racing.

I really think it is one of those things that sailors needlessly work themselfs up over. Often they fuss about a perceived technical advantage while throwing away a multiple of it by applying bad tactics on the water.


Question 2 :




This is easy, a sloop cut main will work best in both setups by far. Simply because you can always depower a given mainsail but never power it up beyond what the sailmaker cut into the sail. Ergo a sloop main can be made to work (well) as a single handed mainsail, but a cat-rigged (singlehanded) sail can often not be made to work well as a doublehander sail by virtue of insufficient curve/draft (lack of power to compensate for the extra crew weight).

So when in doubt get a sloop cut main. Actually I would advise everybody to get a sloop cut main that is optimized for your expected doublehanded crew weight and then just trim into a good shape for singlehanding. Most inexpensive option with overall the best results and the most flexibility. Only when you are really serious in racing singlehanded or some A-cats are giving you a hard time then maybe decide to get a specialized 1-up main IN ADDITION to your 2-up mainsail.

But I wish to underline again that skill and hours practising are always the way to the top no matter what you are sailing. This can't be overstated, simply because skill is so much more dominant in the final outcome then small changes like this. That is when assuming that the boat is dialed in correctly, afterall a small change to my jib did result in a noticeable difference but that was because my jib wasn't working as intended. (It fluttered and collapsed when pointing)

Wouter

Mary,
For what it is worth I'll give you my 2 cents.

In general the cat rig mains are flattter in the head and a bit fuller in the bottom section.
If you get a main cut for sloop rig sailing you can flatten out the top with stiffer battens and get a bit more shape in the bottom by easing the foot a little bit more than you would when sailing with a jib. It may not be as good as a sail purpose cut but it seems close.
I have not had much chance to sail over the last couple of seasons so what I'm about to say may change when I get back on the water again in ernest (but I doubt it). I have purchased a purpose built cat rigged mainsail and I can make my sloop cut main sail work much better. I'll continue to work on getting the cat rigged sail diallled in but the difference is so small I'd be better off had I bought a sloop sail.
I agree with Wouter. Get a sloop cut mainsail and learn to tune it for cat rigged sailing.
Regards,
Phill