Sailing angle to the wind

Discussion in 'Sailing Talk' started by T. W. Nelson, Jul 3, 2016.

  1. T. W. Nelson

    T. W. Nelson Member

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    All things being equal and speaking theoretically could you answer a couple of questions for me ? A. The true wind is coming out of the North 0 deg. and I am on a port tack with my boat 45 deg. off the wind and my sails are set at 45 deg. to starboard from the center line of the boat. I think I am in the safety position. Correct ? B. I now pull in my boom and jib in so they are now 22 1/2 deg. from the center line of the boat. Wouldn't this be the best position to maximize the wind ? C. I am now on a beam reach, wind coming over the port side and have the boom and jib set 67 1/2 deg. out from the center line of the boat. Shouldn't this be , in theory the best sailing position ?

    I hope I have been clear with this question.

    Thank you
     
  2. fhhuber

    fhhuber Member

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    Very close... but sails aren't flat and don't exactly act as rebound planes so the sail angles might need tweaking.

    The sail acts sort of between like a kite and an airplane wing.
     
  3. boat

    boat Member

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    As usual, I do not have a direct answer to your questions but I do have a couple of comments;


    In your first example with wind 0 degrees, boat in any position and your sails parallel to the wind your sails would be considered to be luff and flapping in the breeze totally useless for power other than the parasitic friction of the wind passing over the sail and driving you slowly 180 degrees to the wind.


    I never actually think of setting sails for maximum performance and the angle of the sail in the same context. The head sail is positioned where the air foil reaches its peek position to produce laminar flow over the sail making the outside telltales appear to be glued to the sail and the inner telltales occasionally flutter for a second or two. The deepest part of the sail should then be positioned approximately 45% of the way back from the luff. If the deepest part is somewhere else then the sails are not cut properly. The sail should have enough twist to allow 100% of the sail to be usable. Once this criterion is met you can then note the angle of the sail if that is of interest. Your second example would be in the general area to make this happen but there is a lot to think about at that point.


    It should be mentioned that if you are seeking maximum performance you must think about what “maximum performance” means. Are you attempting to power out of a mark, get maximum speed from mark to mark, are you sailing on flat water or a heavy chop, etc. You must also consider true wind vs. apparent wind. As your boat increases in speed you will need to flatten your sail and make adjustments as the difference between true wind and apparent wind changes. In general, one of the great challenges of sailing is the constant need to change the way your sails are set. If you are looking for maximum performance in a racing environment there is no such thing as “set the sails and simply hang on for the ride”. The relative position of the sails remain fairly constant with respect to the wind regardless of the direction the boat is sailing so long as you are making way using the front of the sail. The sail power comes from the relationship of the sail to the wind regardless of the direction the boat is pointed.


    In general, setting the main uses a lot of the ideas used in setting the headsail. The big difference is the importance of the telltales on the leach of the main – keep them flowing straight off of the main. Perhaps the most important thing, to me, when it comes to the main is using it to balance out the boat. If the sails look perfect and you are healing at a 45 degree angle you will be falling back in the heard. Slack off the main sheet and let the boat get back on its feet. While you want some healing overdoing it will really slow you down. Try turning loose of the tiller/wheel; if the boat falls off or heads up your main is not properly set. Adjust the main until the telltales are flowing properly and you can release the tiller and the boat remains on the correct heading. Remember, if you have pressure on the tiller you are effectively applying a brake due to the drag created by the inappropriate position of the rudder.


    There comes a point in sailing where you are no longer using your sail as an “air foil” but rather a large area of sail cloth that catches wind on the back side to go down wind. This is a whole different subject…


    There are many books dedicated to sail trim which will do a far better job than I could ever do so I must warn that what I have posted here is only my thoughts and may or may not be valid. Spend some time to read and study what the “experts” say and then get out on your boat and see what really works for your specific boat. The points I have made here are overly simplistic and only touch on a small fraction of what must be considered to get “maximum performance” from your sail trimming efforts.


    Hopefully, others can provide additional input and perhaps corrections to what I have posted. They may even give you a specific answer to your questions.
     
  4. T. W. Nelson

    T. W. Nelson Member

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    Thank you for the reply.
    I have had an occasion when the tiller had a lot or resistance on it. Had no idea that something was wrong. Sometime I will have to try the letting go of the tiller see if the boat just keeps on course.
    On trimming the main, I understand that the telltales should just stream or flutter straight back with no luff in the sail. In general, I think I'm supposed to trim the main first then go to the jib. From there on it's constantly going back and forth between the 2.
    I have looked at at few books on sail trim and it just got so deep and complicated that I couldn't absorb it.
    Again thanks for the help
     
  5. fhhuber

    fhhuber Member

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    You can't quite let go of the tiller... The tillers tend to swing hard over if you just let go.

    You can bungee it straight with light tension.
     
  6. boat

    boat Member

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    Fhhuber is correct when it comes to many small boats such as the Capri. Perhaps I was not as clear as I should have been. At my age large and small boat characteristics start to merge together in what little mind I have left.

    Relax any pressure you have applied to the tiller for a “moment” and see if the boat immediately heads up or falls off. If the boat continues to track on course then the sails are pretty well balanced. This is a check I make frequently to insure the sails do not need to be trimmed for any slight changes in the environment. If you don’t feel pressure on the tiller you can assume it is producing the absolute minimum drag which results in more speed and easier handling. If you are sailing a larger boat and have the sail plain way out of balance you can expect a very heavy rudder and fatigue after only a short time not to mention traveling much slower than desired. Typically I find that people tend to over trim the main in an effort to increase speed. When this happens the boat wants to heal over and head up causing the helmsman to constantly pull hard on the tiller to keep the boat straight – not a good thing…. Don’t confuse a balanced sail plane with well-trimmed sails. You can reach a balanced state and have the sails trimmed horrible as you plod along watching others sail past you like you are anchored. The trick is to have well-trimmed sails for the conditions and a balanced sail plain. This is not always easy and typically requires constant trim and balance adjustments as the true wind constantly shifts and you are hit with gusts as well as changes in the current.

    I once sailed 128 miles with a missing rudder when I got near land I radioed in and got towed into port. This was on a 45 foot catch with a full keel. The boat was easily guided using the forward sails as normal (balanced) and the mez for directional control. Worked just as slick as a whistle. Usually, the same can be done on a sloop if you work at it.

    As for the books about sail trim; I would have to agree with you. The discussions can get very technical if not totally confusing to new sailors. Just hang in there and keep trying to understand the basics. In time you will become familiar with what they are saying and the whole process will suddenly be much easier to understand. Practice on the water a lot and pay very close attention to how you set and how it affects you speed and handling. Remember continuously adjust your sails for the changing conditions if you are really interested in speed. If speed is not your goal then simply set back and enjoy every minute under sail – we only have one life!

    Good luck…
     
  7. T. W. Nelson

    T. W. Nelson Member

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    Boat,
    Could you go into this "balanced sails" vs. "trimmed sails" a little more ? I don't understand how sails could not be balanced if they are trimmed. Also which one is done first ?
    Thanks
     
  8. fhhuber

    fhhuber Member

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    Simplified:
    Having balanced sails is having the sails trimmed to minimize load on the rudder.

    You might be sacrificing a little sail power... but you'll also be reducing rudder drag so you may be faster.
     
  9. T. W. Nelson

    T. W. Nelson Member

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    fnhuber,

    If the main isn't starting to luff and the jib telltales aren't fluttering, I would think my sails were in trim. Would they not be balanced also? If this is not the case could you expand on this " balanced sail " idea a little bit for me ?
     
  10. boat

    boat Member

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    Perhaps I used the term “balanced sails” in error. What I should have done is use a term more like “Balance” (period) referring to a number of things required to obtain maximum speed in a sailboat. The ideal situation is to have the sails trimmed so that they look like the pictures in sail trim articles and the rudder with no drag – that could be considered balanced. The problem is this is not as easy as it sounds. First, sails are designed for a specific range of wind speeds. If you exceed the design limits of a sail you will experience excessive heeling which often causes you to have a heavy helm. In this situation the typical response is to slack off on the main sheet to allow the boat to get back on its feet and reduce the load on the rudder.

    However, we cannot be too quick to blame the heavy tiller on the sails. What about the keel? If all of the crew weight is on the stern of the boat the bow will be high and the keel will be trying to surface resulting in even more heeling and causing the tiller to be heavy and the rudder drag in the water. When this happens the first thought is often to slack the main sheet. I would not imply that this may not be necessary but you may first want to shift some of the crew/stowage forward. This will cause the bow to come down, the keel to cut straight through the water and the tiller to lighten. Be careful to not lower the bow too much or the keel will want to dive creating drag. It is possible to have the sails trimmed a light tiller and not over heeling but still slow. If this is the case you may have too much weight forward causing the keel to produce massive drag.

    To be fast the sails must be trimmed for speed, the boat balanced from bow to stern and the pressure off of the tiller. If all of these things are accomplished you will have a pretty good chance of having a fast, easy handling boat - balanced.

    Personally, I slack the main if the boat is level (when heeling) in the water, the sails are trimmed but the tiller is heavy. Once I see this is a continuing problem I consider reefing the main which often allows the boat to heel properly when the sails are correctly trimmed – just my thinking…
     
  11. T. W. Nelson

    T. W. Nelson Member

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    I have read your additional writing a few times now and feel I understand what you were getting at. When I think I have things as good as they can be loosen my grip on the tiller and feel what it wants to do. If it wants to change course start looking at the trim again. Thanks for the new info, I'll try this out tonight.
     
  12. boat

    boat Member

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    good luck - let us know...
     
  13. T. W. Nelson

    T. W. Nelson Member

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    Went out last night in a Lightning, wind was very light. We set the jib, cleated it and then worked on sailing as close as possible to the wind and then falling off if we went to far. And I have to say I got a little too close a few times. We were spread out in the boat so the boat stayed pretty level. I tried holding the tiller VERY loose a few times but never felt the tiller wanting to do it's own thing. I guess we were doing what we were supposed to and therefore had no handling problems. I asked my instructor about the rudder stiffness and he said that a couple things would have to be happening at the same time.
    If the problem pops up again I will be sure to take note of what is going on at the time.
    Appreciate the the guidance.
     
  14. boat

    boat Member

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    If you are within the wind speed limits of your sails you can probably trim them without bothering the pressure on the rudder too much. It is when the wind exceeds the design of the sails that the problems start or if the boat is heavy bow or stern. Normally, light winds have little effect on the rudder pressure.
     
  15. T. W. Nelson

    T. W. Nelson Member

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    Bow heavy ! That's exactly what it was ! Thank you.
     

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