Sorry everyone, lots of issues here.
So say Sydney 38, speed equals lift as keel fin is so efficient. Etchell is similar.
However, real question is constant angle of heel.
Water is denser than air and any movement of keel in the water is the real issue.
So keep the tip of the keel as stationary as possible in the medium.
Next is the gust coming down to windward or on the bow of the boat.
If on the bow, go low and fast to get to the next lift.
Why sail higher but slower into a knock and spend more time in it.
If on the side then it will lift you anyway so again go fast subject to constant angle of heel.
If gusty sail with much more twist
Biggest difference between a good driver and those who can't is the good driver can sail upwind with no load on the helm.
Helm equals brake.
you should always be trying to trim the helm out of the boat.
If you can't your rig set up is not right.
here is a pick from a gusty medium air day, head of main is way open so boat does not load up in the gusts but super fast and letting the keel generate the lift. No load on the helm so no rudder drag.
The Farr 40OD ahead is much more strapped.
Select to expand quoteMAGNESIUM said..
Sailing up wind in strong gusts is it faster to pinch in the gusts or bear off?
completely variable on so many factors. Individual boat design, wave height and spacing.
it is foolhardy to try and pinch in big waves, just end up with no speed and boat hobby horsing. You need to sail around the waves which requires good trimming of the sails to bear away as you pass over the back of them to avoid slamming and then up the face of the next one.
pinching is fine in flat water to shed power and maintain a constant heel angle.
but very much generalisations
Mike Fletcher was a guru back in the day. He used to talk about gears - I use/d this when racing and it worked well for me/us. This is my thinking when racing upwind - I still do this when cruising. I like sailing boats with fractional rigs and big mains.
1st gear - Light winds - sail low and fast to pick up speed, leeches eased, sheets sprung. Headsail telltale might have leeward one starting to flick because you are quite low.
2nd gear - Wind builds up slightly - tighten on - go for speed - both sides headsail telltales streaming nicely. Leech telltale on main (my favourite - 1/4 way down the leech_ is streaming about half the time - playing hide and seek every couple of seconds.
3rd gear Solid wind 15 knots and a little more - plenty of power, maxed out stability, you have more power than you know what to do with. So you need to depower. In choppy water, you need to ease the leeches to stop stall, and go heavy on downhaul to pull draft forward and not use helm much to depower. BUT in flatter water, you can harden up the leech and foot and use power for height - pointing gear. In Sydney Harbour racing - we might change how we depower a few times in a single beat - as we get close to the shore we start hardening up and trading heel for height but then back in the chop after a powerboat or near the heads - we have to keep the nose down more and loosen things up. For most of this gear the windward telltale is on the verge of breaking - lifting up about 20 degrees or so.
4th gear - lots of breeze. You don't worry about telltales anymore - the headsail is luffing and you don't care, the main is luffing for up to 1/3 of its chord down low. The traveller is down, the headsail leads are out and you are trying to keep the boat on its feet. Someone clever is calling the gusts and you head up to meet them to stop you from being blown over. It is important for the headsail to be sheeted out or reduced in size otherwise you get massive lee helm in gusts when the main is dropped to keep the boat on its feet. You steer angles almost totally by heel and talk about getting the heady off and putting a reef in. I use these techniques when sailing other people's boats and even my own cat. It reduces loads on the boat which is always a good thing and it gets you there faster.
Select to expand quotelydia said..
Sorry everyone, lots of issues here.
So say Sydney 38, speed equals lift as keel fin is so efficient. Etchell is similar.
However, real question is constant angle of heel.
Water is denser than air and any movement of keel in the water is the real issue.
So keep the tip of the keel as stationary as possible in the medium.
Next is the gust coming down to windward or on the bow of the boat.
If on the bow, go low and fast to get to the next lift.
Why sail higher but slower into a knock and spend more time in it.
If on the side then it will lift you anyway so again go fast subject to constant angle of heel.
If gusty sail with much more twist
Biggest difference between a good driver and those who can't is the good driver can sail upwind with no load on the helm.
Helm equals brake.
you should always be trying to trim the helm out of the boat.
If you can't your rig set up is not right.
here is a pick from a gusty medium air day, head of main is way open so boat does not load up in the gusts but super fast and letting the keel generate the lift. No load on the helm so no rudder drag.
The Farr 40OD ahead is much more strapped.
Good photo, thanks. Taking the heel angle to the horizon indicates about 30deg off the vertical - would this be what you would take as about the nominal limit for the S38? - as you and G have suggested realise there are many issues involved.
Select to expand quoter13 said..lydia said..
Sorry everyone, lots of issues here.
So say Sydney 38, speed equals lift as keel fin is so efficient. Etchell is similar.
However, real question is constant angle of heel.
Water is denser than air and any movement of keel in the water is the real issue.
So keep the tip of the keel as stationary as possible in the medium.
Next is the gust coming down to windward or on the bow of the boat.
If on the bow, go low and fast to get to the next lift.
Why sail higher but slower into a knock and spend more time in it.
If on the side then it will lift you anyway so again go fast subject to constant angle of heel.
If gusty sail with much more twist
Biggest difference between a good driver and those who can't is the good driver can sail upwind with no load on the helm.
Helm equals brake.
you should always be trying to trim the helm out of the boat.
If you can't your rig set up is not right.
here is a pick from a gusty medium air day, head of main is way open so boat does not load up in the gusts but super fast and letting the keel generate the lift. No load on the helm so no rudder drag.
The Farr 40OD ahead is much more strapped.
Good photo, thanks. Taking the heel angle to the horizon indicates about 30deg off the vertical - would this be what you would take as about the nominal limit for the S38? - as you and G have suggested realise there are many issues involved.
Camera angle not great so less that 15 degrees in real terms.
More heel equals more helm so get it upright so less helm load.
A really fast boat does not feel fast.
Plenty of good info above. One thing is that a G said there is a huge variety between classes and situations, and some boats are proven to go faster with a small but significant amount of weather helm. As Andy Dovell and other designers note, this turns the rudder to an angle where it can develop more lift (or reduce leeway) and take some of the side load off the keel.
As North Sails says "as rudder load is increased through deflecting the rudder, the leeway angle of the boat is decreased. Decreased leeway has the additional benefit of a higher apparent wind angle and the opportunity to produce higher sail force. This makes it is very beneficial to deflect the rudder at least to the angle that produces minimum induced drag for the whole boat and gain low induced drag, a higher apparent wind angle and larger sail force, and less leeway, all of which contribute to better pointing. It could even be useful to sail with the rudder deflected somewhat beyond the loading that minimizes induced drag. The small additional increment in induced drag for a modest increase in rudder angle could be offset by further improved pointing ability."
Some very popular boats, like Laser and (at least in the past) J/24s, Flying 15s and Hobie 16s go better with significant weather helm. However, that's just a few degrees and it requires very quick reaction in gusts to keep the boat balanced; dragging the rudder at 20 degrees is never fast!
Another issue is that the way you handle gusts is affected greatly by the skill of the crew/driver, the quality of the sails and their setting, and the basic design. An efficient medium-speed displacement boat can relish being luffed in gusts, because it will be at maximum speed before the gust hits and therefore cannot really accelerate even if you dump main and bear away. In slower boats or ones with less efficient foils the keel or centreboard can be very heavily loaded and when the wind is very strong, unless the water is flat the boat may slow and develop excessive weather helm and then slow even more, so it's sometimes best to dump sheet and go a bit lower in the gusts to ensure that you maintain good flow over the rudder and keel/centreboard.
However, unless you can keep a boat right in the groove, pinching it may just result in the boat slowing, so less experienced sailors or those with baggier sails may be better off dumping mainsheet and bearing away to keep the boat moving.
Some boats definitely do feel great upwind in a breeze when going at their best, like Tasars, Formula 18 cats and boards. Others have a very narrow groove and feel OK when in that groove but terrible when the bow is up or down just a couple of inches too much (like a Laser).
One really weird thing one often sees is the inshore cruising guys who dump three or more feet of headsail sheet upwind. Easing a few inches is great because it allows the jib to twist open, but easing a few feet makes the headsail a complete bag that heels the boat and flogs to death at the top. They then bear away to keep the sail semi-full and end up reaching around with higher apparent wind. Very odd.
Each boat will be different, but ultimately the best angle is the one that gives you your best VMG.
The excel spreadsheet below is derived from the polars supplied with the boat.
You can see how the optimal wind angle varies slightly dependent upon the wind speed.
If your electronics can record the TWS, TWA and Boat speed, you can calculate your optimal VMG using the supplied formula.
Point of interest: At 14kn TWS the optimal TWA was 32 degrees. But I wouldn't sail at this angle, as even a leeetle bit higher and the boat speed fell off a cliff. I knew that at 4o deg TWA I was only 0.1knot slower than optimal VMG and I had a much wider range before the boat speed fell away, so I always sat around 40deg TWA to give myself some fudge. .
Warning: Factory Polars do not take into account sea state, so I'd only hit these upwind numbers with good sails, no addtional weight (above crew weight) and flat water. Over time, we built up a set of polars for a range of sea states that were derived from the onboard instruments. These were really accurate. I could look at the sea state, grab the corresponding polars, and hit those numbers all the time.
I should say, a huge thing is sails.
Spend a lot of time getting the sails right.
We looked at 6 different patterns before choosing that mainsail then made a few adjustments for where we sailed mostly.
From memory we made the head bit fuller to twist better as we often sailed in tide slop not dead flat water.
Select to expand quoteMAGNESIUM said..
Sailing up wind in strong gusts is it faster to pinch in the gusts or bear off?
Are you trying to get to an upwind mark as quickly as possible? Or simply trying to go faster? Because the answers are completely different for either.
I would trust and assume that he is talking about getting to a race upwind mark faster. Of course all the other comments above are spot on but then the race starting line and first work comes into it - with all the other boats obviously - so in a mixed hcap fleet you have the added complication of how high they sail to the wind to you - based on vmg height. Try a start with a Holland 11 or E22 or Soling under your lee bow and you are both in clear air - they will squeeze you up till you have to tack way if you can otherwise you will sag out the back door. So whatever the wind strength you must have 3 modes off the starting line (and all round the course as relevant) whatever the wind strength - the 3 modes being vmg, higher than this, and lower - it depends on the inmates around you and how they are sailing. There is only 1-2degs course difference in each mode but some sail trim difference. Then getting into the windward mark often needs high mode to round it if that gets you around without another tack - but don't do this from a long way out - vmg is the best mode for most of the work.
Two things.
Almost all driver drive too high and don't let the boat keel do the work.
Tear the telltales off the front of the headsail and see how well you can drive upwind. (This an elite training exercise by the way)
Watching the telltales is not a very reliable way to go fast.
Getting the bow down and constant angle of heel is!
Headsail trimmer secret, if you have a driver not getting the bow down, you ease the sheet so they have too because they are watching the telltales not the boat.
Have a look at Shaggy's table for TWS 6.
4 degrees of TWA is 0.5 knot of boat speed
However remember the table is TWA as AWA will be higher.
Lastly, Shaggy will have gear calibrated properly because he is Shaggy.
Almost no boats have the calibration properly done as the people doing it following the process but don't understand it.
