Block to Block, or By Feel?

I'm looking for advice going upwind. I've heard many sailors say that one should sheet in the main as hard as possible, implying that it can't be overdone. I sail a Spitfire, which has a fairly fat head, although not as extreme as this year's sails. I have noticed the boat stalls if I sheet too hard upwind. Is the 'block to block' advice outdated, related to pin heads, or just as good as it ever was? Does the downhaul come in to play at this point, to reduce the profile of the sail, as seen from the front, and hence reduce drag? But that would alo reduce power wouldn't it? Now you can see I am somewhat confused! Unfortunately I don't have another Spitfire to sail against at my club - but I love it!
Simon

I find that it is a combo of sheeting in as much as possible - so I guess the "block to block" statement is correct- but also paying attention to the tell tales. Sometimes, however, you can never sheet in enough to get the windward tales streaming which probably means you need to foot off some.

Get Rick and Mary's "Catamaran Racing" for the 90s. I seldom crank in my Hobie 18 magnum all the way unless the winds are around 25k and I'm starting to travel down. Ditto with the downhaul.

Wyatt

I guess a key element to my question is if the newer design (fat top style, rather than pin head) mainsails can be oversheeted upwind.

Does Rick & Mary's book describe these newer designs? I am fairly new to sailing, so I am not sure if fat tops were around in te 90's.

Simon

Well we're not racing Hobie 16's here, but modern boat with real trim controls,

Oversheeting the modern mains can in some conditions kill upwind speed.

Pretty much you always went the squaretop to twist off a little bit. if it is in too far then you are just creating alot of tip vortex drag.

Pretty much you increase downhaul together with mainsheet. This keeps the twist profile the same while flattening the whole sail. This is fast in the right conditions.

Go over to the F16 forum and do a search on trimming and tuning the sails. Over the years we have covered this topics plenty of times. Spitfire sail trim should be very comparable to F16 sail trim.

Wouter

Don't get this book if you are really looking to make the boat go. The book is too generic to be of use. Yes, guys, I have the book on my shelved as well. The book does not deal with squaretop sails and does not focus on the interaction between downhaul, mainsheet, squaretop and prebend and this is exactly what you need to read and learn about to make the modern rigs go.

Wouter

There has to be a way you can say something like that without sounding so confrontational.

Wouter: You just can't help yorself. Is the Hobie 16 jab needed?
Not that a low tech guy like me would understand any of this sail trim stuff, but I think you can stall any sail.
(they splanes this in da book)

The book is a great book about sailing and racing.
I refer to it every year and still find useful things to learn or refresh my memory.

I welcome you to come jump on a H16 and race 30 or 40 boats and show us how it's done. I'll find you a boat.
With your superior knowledge, it should be easy.

Children, stop bickering.

Simon, As wouter says, fat top sails to not respond well to cranking lots of mainsheet on.

Having sailed a Spitfire around the IOW a couple of years ago in various conditions I have to agree with Wouter, you need to use Downhaul, mast rotation, traveller and mainsheet. Quick and simple guide.

Very Light wind.

moderate mast rotation, bit of downhaul to flatten the sail a little, moderate mainsheet tension (to try and keep the leach telltails flying)

Light wind.(only one or none trapping)
Max mast rotation and mainsheet tension to keep the leach telltails flying.

moderate wind (2 trapping)
move the mast rotation back a little to allow the leach to stand up some more, more mainsheet tenstion, increase downhaul and mainsheet tension as windspeed increases.

higher wind
More downhaul, more mainsheet tension (but keep the leach tell tails flying), traveller out a little in the higher range.

Very windy
max DH, ease traveller and play mainsheet.


At some point you may also want to move the plates up a little.

Fat top sails need care toget the best from them. Oversheeting kills them.

Simon - Block to Block works well on a Hobie 16 in the proper conditions . Obviously - if the above quote is correct - you should not do it on you boat. I don't know the Spitfire, but as Wyatt said (Hi Wyatt), you rarely (I thought never) do it on a H-18, for example. So block to block is not a standard. Try sailing a Stiletto block to block - you can't.

It depends on the type of boat and the wind conditions. Sailing block to block is often not the fastest.

Learn to read your telltales.

And read Rick's book. Catamaran Sailing for the 90's. It may not cover every design the the basics are all the same.

Mike Hill
www.stlouiscats.com

I have sailed several squaretop Formula 18s (Tiger, F18, Infusion). Those sails like a fairly stiff leech but it can easily be oversheeted so you have to pay attention. The top will stall first so you will have to sheet in to a stall then ease out to where the back telltails stream to see where the proper sheeting is for the wind conditions. I have found that even in very light winds the downhaul likes to be snugged on. This will open up the top as well. Not too much but it is something that you need to play with. The masts are getting bigger sections and that will throw another wrench into the mix...you will need to look closely at rotation.

Later,
Dan

Robbie Daniel (Tornado Olympic campaigner and winner of the recent Alter Cup on I20's) tells me to set the main more by looking at the leech shape than by watching tell tales. With boat on the shore, stand behind the boat on centerline looking up the leech with main sheet in hand. Sheet in until you see the leech of the sail standing up on centerline, then go a bit further. You'll see the leech hook past centerline (to windward). That is too far. Back off the centerline. Get to your normal helming position and view the leech shape. Try to burn this shape into your memory, as it's what you almost always need to achive going to weather. You will need more or less sheet tension to get there depending on wind strenght etc. You cannot just mark the main sheet at what looks like the right position, since the sail will need more sheet or less sheet under different wind strengths. I'm just beginning to use this technique...not sure if I've got it down perfect, but time will tell.

Another gem I picked up from the Charlie Ogletree at the Miami OCR last January...use the downhaul only as a gross adjustment to get enough power to fly the hull and not pop rapidly. Then, with the crew sheeting the main, adjust DH so crew only has to ease/sheet about one fore-arm's length with each puff to maintain the hull out the water. If you're popping up to quickly and needing to dump too much main, put on a little more DH. It takes some practise to have both crew & helsman coordinating/communicating and trusting who is going to respond to each gust, but when we get this technique right, we just scream up wind and the boat suddenly feels like it's on rails. Each puff squirts us forward instead of heeling the boat. Awesome!


Mike.

Block to block is only good if the mast rake is perfect for the conditions.

Yes, learn to read the tell tails. I like to use leech tells for making the adjustment. The leech tails should not flow aft, they should hook, flow, hook, flow.

Take a look at this placement suggestion. This is for a Hobie 16, but is pretty generic to any sailboat.

Hey guys, thanks for some good posts.
Two questions:

Scooby, you mentioned using max mast rotation for light wind (0-1 trapping) - I assume you meant max mast rotation for upwind setting? I guess that varies somewhat by boat design Where is it most commonly, the shrouds or front of daggerboard well?

Regarding reading main telltales, I assume that the advice given is only for sloop rigged boats? On my unirig H17 I use the upper and lower telltales on the draft of the sail (lower to set traveller and upper to set mainsheet) and haven't found the leech telltales all that useful (of course there's always the distinct possibility that I have no idea what I'm doing...). I also steer using the forward telltales in windshifts. So is it that with a jib, the main is always headed and as a result the forward telltales are irrelevant? Can you use just the leech telltales with a unirig, and if so how are they used? Using leech telltales with either unirig or sloop, how are you using them to independently trim traveller and mainsheet as is possible using upper vs lower forward telltales?

Jerry

Ask this guy (attachment). He knows a little about making the H17 go. I know your out there Matt

Jerry:

Get "Catamaran Racing for the 90's". There is a whole chapter by Carlton Tucker on the Hobie 17 and he explains the telltales good. The book will also make you a VERY good sailor in less time that you can learn on your own.

Doug Snell
Hobie 17
www.tcdyc.com

Allow me to clearify this.

I'm not saying at all that the suggested book is bad in any way, just that it has a limited use with respect to finding optimal trim with modern large squaretop mainsails. The book has a different intended usage, it gives a good generic method for sailing your catamaran, no matter what design specifics it has. As such it gives cat sailors a basis to expand their skills upon.

This expansion (on modern squaretops) is not really covered in the book, the author decided that this was outside of its scope. Nothing wrong with that. It just aims at a different usage.

Wouter

I mean as much as you can get - up to 90 degrees, i.e. the spanner poointing along the front beam.

In less wind you cannot have a sail this full going upwind, in more wind you need to de-rotate to ensure the leach of the mainsail stands up more.

Simon, would you say going up to 90degrees of rotation on teardrop shaped masts is a generic setting for very light wind conditions?

I agree that it will power you up, but the drag, the drag..
I prefer to pull on quite a bit of downhaul to flatten the sail in very light wind to reduce drag, and keep the mast less rotated than 90 degrees. Power to drag ratio is what keep you going in very light winds in my opinion.


Mike, about the downhaul thingy. We rarely sail in winds so stable that we can do what you describe, so the skipper runs the downhaul. Rule is that skipper use the downhaul to control power while crew controls the leech for pointing and fine-tuning power. Getting this right is very much like running downwind with the spi, teamwork and getting the feeling for it. If we goof it up, crew is responsible for letting out mainsheet to avoid a capsize and skipper waits as long as he dares before luffing up.
When I study the video from Athens, I can only see the french team sail this way (skipper on downhaul), but perhaps the coverage of the other boats was in pretty stable wind.. I dont know, but Martin Strandberg advocated skipper on the downhaul in gusty wind. Neither the swedes or the french did too well in Athens

I differ on mast rotation is light winds. I rotate less. I feel a very full sail is just draggy and slow in the really ligtht winds.

Wouter

Wouter:

Yea new sails are fun to figure out. I have a 190 sq ft Pentex reacher and go along with my Pentex squaretop on my Hobie 17. Still trying to learn the reacher as this is a LOT of sail on this boat. It is roller furling so at least it is easier.

Doug Snell
Hobie 17
www.tcdyc.com

Charlie O., arguably one of the top 5 cat sailors active today, gave me this tip. As stated before, DH only for gross adjustments, fine tune with main. Previously, we were trying to adjust DH in the puffs...and found we'd over compenstate and were too slow to gain much before the puff had passed by. I've used Charlie's method in a couple of regatta's now and once we get in the groove with it, the boat handles like nothing I've experienced before. This is not something just for stable winds...you are compensating for gusts, even big ones, but with the main sheet only once your are in the ball park range with the DH. Helmsman can concentrate on steering the swells and does not need to luff if the crew is on the ball.

All,

No, in very light wind you need to keep the air attached so you cannot have a full sail, you need it to be fairly flat.

as I said, in light wind (so 0 wiring to one wiring you need the power).

Very light wind you need a flatter rig.

if you re-read what I say initially I hope it's now clear what I mean:

Thanks Simon. Must have been more tired than I tought last night, after a 14 hours working day, it is very clear now.

I remember we tried about 90degrees rotation and a tight sheet three years ago going upwind in what you describe as light conditions. It felt slow and bound up, but I dont remember if we had a large separation bubble on the windward side or what. This was before we had a GPS, so we will definately put it in the "go fast" book and test it again as soon as possible.


Mike, I noticed what you wrote in your excellent report from MORC and the NAs about how to run downhaul. It makes a lot of sense, and Charlie is an autorithy.
In our prevailent conditions we have quite strong gusts when on the trapeze. We need to run the downhaul, or dump armloads of sheet combined with luffing up. Of the two, we choose the latter.

Great fun, Doug.

Wouter

Rolf, I said sheet tension to kee pthe telltales flying, not tight.

On the Spitfire (and my 17) I woould say it was "one hand, no leg bend, not actually that tight" tight...for the "light" 0-1 wire conditions..

As opposed to "max tight" being "both hands, bending and extending legs, bending boom and creaking tight" tight



I would also suggest adding many telltails to a sail when learning and then mucking around with Rotation, Downhaul, mainsheet and traveller untill you

1, Work out what is fast
2, work out which telltails you need to use in which situations (and which ones to ignore).

I think I have around 10 sail telltails (on each side of the sail) plus 4 leach telltails on my Inter 17 sail and I don't use all of them in all conditions.