why do people use compasses?

Discussion in 'Laser Talk' started by Gideon, Mar 8, 2011.

  1. Gideon

    Gideon New Member

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    Hi, i was wondering why people use compasses on their lasers
    Is it because you sail in open sea with no real point of refference?
    I just don't get it :D, not being disrespectfull!
     
  2. Deimos

    Deimos Member

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    The wind is continually changing direction. Often oscillating, sometimes oscillating as it shifts. Thus when on a leg, at any moment in time you have to use the wind to best advantage. Think of a beat; in theory the wind will be blowing directly from the windward mark to the leeward mark (at least the Race Officer will aim for that). But the wind direction is continually changing so at one moment the starboard tack will allow you to sail more directly to the windward mark, then a bit later the port tack will be the more direct route. As you need to tack to get to the mark anyway, far faster to take the more beneficial wind direction at any moment in time. Same applies on a run (i.e. which gybe to sail on and what course to take) but if you are getting to grips with the concept, think of the beat to start with.

    But, the wind is just one aspect of the race. Taking the beneficial tack (wind) out onto disadvantageous tide in the lee of something on the shore might be daft. So the wind direction becomes one aspect of your tactics. One thing to consider along with everything else.

    Similarly, as you get closer to the lay-lines (on a beat), so you will need to consider your position on the leg in relation to the wind direction and may want to tack on a wind that is not too bad (or good) because you need to get closer to the mark rather than bouncing of the edges. So what you call a "good" or "bad" wind direction will probably change as you sail the leg (as your aim is not just to sail to windward but to get to a mark).

    As you are beating so the compass will tell you your heading. Checking it periodically will tell you if the wind has headed or lifted you (headed meaning the wind moved closer to your heading, thus you had to bear away). When sailing along you tend to be continually making fine adjustments to your heading. The wind often changes gradually so it it a lot easier to detect with a compass. Having a shore can help detect a wind shift but tide, and leeway can make it harder. Similarly, on rounding the leeward mark, you can remember the wind from the last beat and immediately know the better tack to start on (i.e. without having to wait for a shift).

    Also, a start line is rarely at right angles to the wind direction. And even if it is at the 6 minute gun, it may easily change as the wind shifts. A compass will allow you to detect which way the start line is offset to the wind (biased) and thus which end it the best (closest to the 1st mark).

    Also, ...

    It is not as complex when you actually use it as it is when you try reading an explanation from somebody not so good at explaining things (e.g. me). Some people like tactical compasses which have different scales from a normal NSEW 360 degree scale. Tactical compasses make it easier to check the heading/shifts on different tacks.

    Hopefully somebody else will post a few lines and explain it decently - but until then you can puzzle over mine.

    Ian
     
  3. Gideon

    Gideon New Member

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    thnx Ian
    that really explained alot!
    srry for making you write that much:eek:
     
  4. torrid

    torrid Just sailing

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    I'll give the Cliff's explanation:

    It's for detecting windshifts, not navigation.
     
  5. dredies

    dredies Member

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    It's great at measuring that shift you just missed :D
     
  6. mental floss

    mental floss Member

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    I seem to use it so I can look fast in the parking lot, even if I'm not fast on the course.
     
  7. gouvernail

    gouvernail Active Member

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    It's one more source of information.

    Clouds, flags on boats. Angles of other boats. Color of water and texture of water.

    Tell tales.
    every tool has a use.
     
  8. AlanD

    AlanD Former ISAF Laser Measurer

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    Yep, but where it really pays off is when to ignore a lift because it's still a relative knock. Or ignore a knock because it's still a relative lift. Compasses are very useful for looking at mediums and making calls upon those mediums being met or not met. They also make chosing which side of the course to go out on easier at the bottom mark.
     
  9. rmraya

    rmraya New Member

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    I normally go sailing on open sea and my regular circuit is a triangle formed by two buoys and the port.

    The first buoy is 2 miles away and I can’t see it right after launching. I know where it should be, so I use the compass to keep the course until I see the buoy.

    After mounting the first buoy, I gybe and head to the second one, but it is also 2 miles away and the compass helps me in keeping the right course.

    Going back to port is easier because I can see the buildings on the shore and have good references when the sky is clear.

    Rodolfo
     
  10. laserxd

    laserxd Member

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    personally I wouldn't want a compass on my laser, it adds excess weight and I like to sense the wind shifts while keeping my eyes on the water, by the time you figure out that there is a shift on your compass, I will already have taken advantage of the shift.
     
  11. Eric_R

    Eric_R D10 Secretary

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    It doesn't weigh much at all (and it's in the center of the boat), plus if and when they allow electronic compasses, it'll weigh even less.

    If I'm not close to land or in a new area, I take the compass and use it. I like to get some reference points for when I sail upwind beforehand and know where I stand.
     
  12. laserxd

    laserxd Member

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    In your case a compass is definitely usefull but, I'm still not sure that I personally would want one on my laser regardless of the weight.
     
  13. Sailorchick

    Sailorchick Member

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    I've just started using a compass (lovely Xmas pressie) and it is a useful tool. It shouldn't be the only thing you look at but it is helpful for checking you are right about shifts, and as Alan says checking that the lift/header you are on is actually a real lift/header. I'm still learning as need to make sure I keep my head out of the boat whilst making use of compass - it is very easy to focus too much on it.

    If you are going to sail on the sea they can be useful for when weather conditions deteriorate too. I've been caught out before at Swanage where the wind died and the fog descended. I would have sworn I was pointing for home but when the ribs rounded us up I was a long way off course (along with lots of others) and actually heading for the cliffs instead. Those with compasses knew which way home was.
     
  14. arm

    arm arm

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    Hola.

    I use mine for thursday night racing and for sunday races. Both are mixed fleets between big spin "A" boats down to centerboard classes. We go around fixed marks depending on the wind direction and strength. I use the compass on those races to try to figure out what is the bearing between marks so I can get there without depending on the big boats.

    On Laser only races, I barely look at the compass because shifts get detected against the shore line and....I am busy enough taking care of being right side up, etc.

    Be well

    Antolin

    ps still using gloves to race the Laser
     
  15. Jakeee

    Jakeee Member

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    I dont need a compass I can sense the wind shifts with my windward ear, the wind whistles with differant tones depending on it's direction:D
     
  16. Merrily

    Merrily Administrator Staff Member

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    Is that like my April Fools joke of a few years ago--sails that change color when they are properly trimmed?
     
  17. Jakeee

    Jakeee Member

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    a bit like yours, but mine is better :D
     
  18. rmraya

    rmraya New Member

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    I need to find a compass that tells me in a loud voice when a gybe or tak is complete so I can move the tiller back to center without worrying.
     
  19. Gideon

    Gideon New Member

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    is this an april fool's joke or are you for real :D
     
  20. rmraya

    rmraya New Member

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    Don´t you think it would be nice having a compass that acts like a coach?
     

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