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Old 31-01-2012, 15:59   #136
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Re: Sailors Don't Know How to Set Sails ?

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Originally Posted by s/v Jedi View Post
Sailing upright is not very macho so many boats put the rail down in the water anyway. \

ciao!
Nick.

I perfer to be a wuss! I probably get my max waterline around 5 degrees of heel anyway! If my rail is in the water thats pretty serious and I'm doing something really wrong!
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Old 31-01-2012, 16:01   #137
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Re: Sailors Don't Know How to Set Sails ?

Okay, I'll give it one last try in as simple words as I can manage
(I simplify a bit here and there too )

The keel balances the rig. You can't change the trim of the keel, so you have to adapt the sail trim so that it keeps in balance with the keel. If you get weather-helm, you are not balanced: you heel too much, and the shape of the part of your boat that is underwater has become very asymmetric because of that heeling. This has transformed your boat into one big rudder that wants to round you up into the wind. Reef your sails so that the boat rights herself again and weather-helm will reduce too.

That's it. When you got that under control, you can get into the books and learn how to de-power sails without reefing so that you can delay reefing or create "half reefs" by changing the sail trim.

Before you dive into that, I would suggest to first learn about the gearing of your boat. How to switch to low gear when you're sailing upwind in big seas.

ciao!
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Old 31-01-2012, 16:02   #138
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Re: Sailors Don't Know How to Set Sails ?

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Originally Posted by foolishsailor View Post
Not true. The designed wetted surface is usually optimised to increase waterline while reducing wetted surface at a given angle. The optimal efficiency of a sail plan is zero degrees of heel as that presents the most surface as to the wind. So in light air where you are not reaching your hull speed you get maximum efficiency and as the wind pipes up the boat heels and the water line increases to give you a faster max hull speed and even though the sails don't present the same surface area to the wind there is ample power and at this point less wetted surface and more LWL is more important for speed.
I've raced on five or six different race boats, and all skippers put weight on the lee rail in light conditions, targeting about 15 degrees of heel. They all said this was because the boat was designed to go upwind with some heel.

I'm not sure about the hull design issues (water line length wouldn't really matter since you're a long way from hull speed in light air), but one important consideration is that by heeling over somewhat, gravity helps the sails keep their shape, which can have a huge impact on keeping the air attached to the sail.
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Old 31-01-2012, 16:07   #139
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Re: Sailors Don't Know How to Set Sails ?

On a thread a year or so ago on a similar heeling thing Bob Perry responsed the best heel was 0.

Meanwhile I don't care how someone else sails their boat!
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Old 31-01-2012, 16:10   #140
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Re: Sailors Don't Know How to Set Sails ?

One more point: Conventional wisdom has it that some weather helm is a good thing. It rounds the boat up in a moment of inattention from the helm (something I'm particularly known for, I'm afraid), but it also provides a wee bit of lift to windward. Think of the rudder as providing more lift than drag when it's only cocked a few degrees. Makes sense to me, though I'm only repeating the lore.

I like to have 2-4 degrees of weather helm, but will reef at 6-8 if I can't get rid of it some other way.
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Old 31-01-2012, 16:30   #141
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Re: Sailors Don't Know How to Set Sails ?

cwyckham has described dinghy sailing in light winds. It's full sail shape that helps you move forward in light air and I generally heel the boat to leeward in light airs.
kind regards,
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Old 31-01-2012, 18:29   #142
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Re: Sailors Don't Know How to Set Sails ?

I didn't start the thread, just a reply. I will say, the bigger the boat the more difficult it becomes. Geared wheel steering dosen't help.
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Old 31-01-2012, 21:09   #143
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Re: Sailors don't know how to set sails ?

This also harks back to the thread on whether one should take lessons or not...

...it is nigh impossible to learn optimal trim without either racing extensively or taking lessons. Not because everyone isnt capable - because you can still cross oceans and sail around the world very successfully with shitty sail trim and not know it - and in fairness be totally happy.

..guess it comes down to different strokes for differnt folks - but why do something poorly if you know it can be done better?[/QUOTE]

By all means, let the lessons begin....
Do you have anything to share?
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Old 31-01-2012, 21:14   #144
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Re: Sailors Don't Know How to Set Sails ? Say it ain't so

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Originally Posted by foolishsailor View Post
Couple of tips for upwind...

1. Dont think of your sails as two separate sails - think of them as one large sail

2. You cant learn to trim if you cant see what you are doing. Add tell tails to your sails


3. Very generally – flatter in heavy wind, fuller in light wind. When the wind pipes up tighten all your control lines such as outhaul, downhaul/Cunningham and vang (however with vang in really heavy air you want to open up again…

Jib: 3 sets of 3 tell tails on each side – use different colors such as red/green
Set 1: 1' aft of the luff spread vertically from the top 1/4 of the sail to the bottom 1/4.
Set 2: mid way between luff and leech same height as the 1st set
set 3: 1' forward of leech spread same as previous two

Main: Depending on size usually 3 sets of 3 or 4
Same spread as above on head sail except:
Set 3: should be attached to the leech of the main. Be carefull how you attach them so that there is not a bias to the way they stream - this will make it hard to see trim in light airs. You want them streaming off the end of the sail. Also if you have battens you want them off the battens and importantly off the top batten.


4. There are three sides to “white” sails and each generally has a line that controls it.


Main:
Luff: Halyard and Cunningham/Downhaul
Leech: Boomvang, Sheet and Backstay
Foot: Outhaul


Jib:
Luff: Halyard
Leech: Fairlead
Foot: Fairlead and to some extend Sheet

Basic trim tips for jib:
All 3 sets on both sides should be streaming aft. Ideally the ones on the windward side should be just “lifting” – ie pointing just above horizontal. Ease the sail towards the tales that are not flying.


To get them all flying you will need to adjust the fairlead. Trim the sail until the bottom tales are flying. If the top tales on the inside are not flying then move the fairlead forward until they do., if the ones on the outside are not flying ease the fairlead back until they do.


4. Always optimize your headsail before your mainsail.


Basic trim tip for main upwind:


Tip 1: You want the telltales that are streaming off the leech to be flying 50% of the time. That means you don’t want them streaming hard aft instead you want them to fly, drop, fly, drop about 50% each. This gives you your optimal attached flow and entry angle for the main.


Tip 2: Once you have the tales flying you can optimise the sheet and vang tension based on the angle of the aft end of the top batten.


In light airs (0-8kts) it should point 5-10 degrees to weather (0degrees would be parralell to the boom, this can be seen by looking up the sail from under the boom and once you get used to it you can spot it easily from the helm)


In Med Airs (10kts -15kts) it should point parallel to the boom


In heavy airs 15kts+ it should point to lee of the boom.


Triming the main pulls the batten to weather (once already close hauled) and easing it opens to lee





Tip 3: Use your traveller


To get the above right your traveller needs to be involved. You always want your main as close to the center as possible until it creates too much weather helm. Generally in light air you will have the traveller all the way up on the windward side of the boat and the main centered and in heavy air you will want the traveller all the way down on the lee side of the boat.


Tip 4: Weather helm is dangerous, hard on your equipment and slow – fix it to go fast


When racing you never allow more than 5degree of weather helm going up wind and it is a good idea to stick to that as well when cruising as it will save wear and tear and power drain on your autopilot as well as slow you down.


Quick adjustments to solve weather helm issues using main


1. 1. “Drop” the traveller – lower the traveller to lee until the helm feels more balanced


2. Ease the vang, ease the sheet, or tighten backstay – this opens up the leech at the top of the sail and depowers the top of the sail. As this is a long way from the center of effort the power up here creates a lot of heel and even a small depowering by opening up the leech works wonders.


3. Shift the draft of your sails. By tightening the luff of your sails you move draft forward by easing you move it back – you can work this one out on your own boat

Number One Tip: Look at what you are trimming.

If you look at the sail when you are adjusting it you will clearly see what is changing. For example if you look at your main when it is sheeted really hard in and you ease the sheet even a couple of inches you will see a dramatic change in the position of the leech and it is clear what adjusting that line, even a bit does.


My quick brain dump – hope it helps someone…
and add your did, I did not read far enough.
Thanks for you post
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Old 01-02-2012, 03:44   #145
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FoolishSailors posts on sail trim and keel effects of weather helm are spot on.

As to why there are different hull shapes and keel shapes? Lots of different designers of crusing boats is one.

For race boats it is usually a result of the racing rules putting constraints on hull design and a fair amount of theory and science. As for optimum heel, it will also depend on the boat hull and keel design as it has been constrained by the rules. Some IOR boats were made beamy in purpose and WL length increeases significantly with heel so max hull speed is reached with more heel.

For most (hate to say all) boats heel will increease weather helm for the reasons described.

Nick is also spot on about gearing. It is important and I still am no expert but I only understood it after sailing with a very successful J24 skipper. I asked about gearing and he showed me. I asked what mainsail inversion was and he showed me. I asked about proper backstay use and he showed me.

Although I read voraciously when I decided to try and be a racing sail trimmer, I didnt learn it until I did it with experienced racers, so I agree 100% with the poster who said something like, forget the theory go out and do it. However I do think you need both. When I was looking for crew I gave each one the North Sails J24 trim guide and the j24 race training videos. If they did not take the time to read and watch that stuff they pretty much didnt work out as crew.

The best part is there is always something to learn. When you are "racing" another boat the best tool is power of observation. Constantly compare your condition to the to the other guy and think about whether you can improve or not. It is really hard to do this sailing solo. That is why dinghys and one design boats are good. It gives you the best feedback on how your skills are improving or not.
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Old 01-02-2012, 04:22   #146
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Re: Sailors Don't Know How to Set Sails ?

FoolishSailors, thankyou for some very useful stuff. It is really appreciated.

On the reefing to go faster, trim to ease the helm issues I haven't seen any comments on 'Stalling' as an aircraft wing does. This occurs when the flow can no longer follow the back side (top) of the wing so the vacuum side of it is lost, and drag increases too.
With the keel it is designed to be just big enough to carry the designers idea of a full sail load, and no bigger. The designer hopes the boat will sell better if it has reasonable speed, too big a keel will slow it down, too heavy and it will slow down. Then he adds to allow for the expected sailing conditions and comfort.
Too much side load will also stall the keel which is why reefing at certain heel angles doesn't reduce boat speed. If the rudder forces are high then it is also stalled, working like a plank dragging through the water, not a sleek shape slipping through the water.
So, keel and rudder are designed for a good sail trimmer who balances the boat to reduce drag and off-sets sail driving power with leeward forces to find the optimum for the hull design. Prototypes may be modified, racing boats certainly are, in spite of the expertise of the designer, improvements will be made based on experience.
We should be sailing the same way, not assuming that the boat is 'right', but trying different things to get each passage closer to the 'sweet spot'.
That's why we sail instead of motor, and why racing is so popular, and cruising is such an addictive life. It's the journey, not the destination. Surely there's time on a three month voyage to ponder what would happen if that line was tauter, or the jib pulleys were moved forward to get rid of those wrinkles. When it's right the boat runs easier, the ride is better, and the destination moves nearer. Isn't that what the cruiser wants!
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Old 01-02-2012, 05:40   #147
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Re: Sailors Don't Know How to Set Sails ?

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...For race boats it is usually a result of the racing rules putting constraints on hull design and a fair amount of theory and science. As for optimum heel, it will also depend on the boat hull and keel design as it has been constrained by the rules. Some IOR boats were made beamy in purpose and WL length increeases significantly with heel so max hull speed is reached with more heel.

For most (hate to say all) boats heel will increease weather helm for the reasons described...

Nick is also spot on about gearing. It is important and I still am no expert but I only understood it after sailing with a very successful J24 skipper. I asked about gearing and he showed me. I asked what mainsail inversion was and he showed me. I asked about proper backstay use and he showed me.
The old IOR rules did create some mad boats. But even without those rules dictating hull design you instead have misplaced consumer desires creating strange hull shapes that in some ways mimic the hulls that came out of IOR rules. For example consumers are generally more concerned with huge cockpits for entertaining and massive aft cabins then they are with safety and performance so you get these big assed bene's and jenne's that look like mini W60s - and also share some of the dangers of vanishing stability as well...

From How much more efficient is a heeled boat? 35% more efficient! - SailNet Community

"The drag coefficient of this boat was calculated to be .34 upright, and only .22 heeled. So, its shape is 35% more efficient when heeled (at between 3-4 knots in the water and between 10-15 degrees of heel) than when upright. "

This was done with an '81 Hunter 25 but the hull shape would be similar to the modern fat ass boat. This increase in efficiency is a byproduct of decrease in wetted surface and not increase in LWL as they were not near Max Hull Speed. You would not find the dramatic decrease in wetted surface in more Blue Water type boats but you still generally find an increase in LWL at heel specifically because designers recognize that crusing monos will spend most of their life at some angle of heel...

Nick is spot on with gearing and understanding the way apparent wind develops and changes as boat speed and wind speed increase but understanding gearing usually comes after the understanding of good sail trim and the ability to look at a sail and its relationship to the apparent wind.

edit: Nick also spoke about incorporating the sea state into your mental calculations when dealing with sail trim - i.e. a sail trim setup that is fast but slow to accelerate in flat conditions (i.e. flat) and a sail plan that is fast to accelerate but lower top speed in heavy seas where you wont hit your max hull speed (i.e fuller than normal for wind conditions w/o inducing excessive heel). These are important concepts for staying fast and safe in heavy conditions but usually beyond the scope of someone who is still concerend with understanding basic sail trim

Quote:
Originally Posted by Eleven View Post
FoolishSailors, thankyou for some very useful stuff. It is really appreciated.

On the reefing to go faster, trim to ease the helm issues I haven't seen any comments on 'Stalling' as an aircraft wing does. This occurs when the flow can no longer follow the back side (top) of the wing so the vacuum side of it is lost, and drag increases too.
Stalling is illustrated by your tell tales very clearly. When the tales on the lee side of the sail are not flying it is illustrating detached flow - detached flow = 'stalling'

By the by - thanks for all the positive feedback...
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Old 01-02-2012, 06:28   #148
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Re: Sailors Don't Know How to Set Sails ?

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Originally Posted by foolishsailor View Post


edit: Nick also spoke about incorporating the sea state into your mental calculations when dealing with sail trim - i.e. a sail trim setup that is fast but slow to accelerate in flat conditions (i.e. flat) and a sail plan that is fast to accelerate but lower top speed in heavy seas where you wont hit your max hull speed (i.e fuller than normal for wind conditions w/o inducing excessive heel). These are important concepts for staying fast and safe in heavy conditions but usually beyond the scope of someone who is still concerend with understanding basic sail trim




By the by - thanks for all the positive feedback...

I certainly appreciate your input.
Most of my sailing is in the Irish Sea, lumpy on the best of days, and have been experimenting with trim for the sea state
Tend to have the sails fuller at lower part, and twisted out at the top for upwind. Which for some reason is about the only point of sail I get to be on, for some reason the wind seems to follow the bow of my boat where ever I want to get to
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Old 01-02-2012, 06:40   #149
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Re: Sailors Don't Know How to Set Sails ?

There have been some amazing and in depth replies and judging by the amount of posts it shows a few things.
Setting sails is not as strait forward as it first seems and is in fact a complicated subject that relatively few really understand.
If there is such a thing as an average sailor I would suggest like me we do the best we can and can sometimes be puzzled when we pass another similar boat or they pass us.
Besides the control we can use on our sails there is a lot we have no control over and without going into it I am sure there are differences it sails, age, shape, materials, battens that make a lot of difference.
I have learnt a lot so thank you for your contributions but fear that there will never be enough time in three life times to always get it right.
Hopefully I will remember enough to get it a little more right but the main thing is to carry on trying and experimenting.
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Old 01-02-2012, 06:51   #150
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Re: Sailors Don't Know How to Set Sails ?

The hunter 25 in the test is a cherubini not a fat ass model. The hull had a year of growth, the increase in efficiency mostly came from getting the grass out of the water. They also don't mention the outboard, was it getting out more with heel?
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