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davidpm 09-23-2011 12:53 AM

Make the mark
 
I would like to hear the tricks and techniques folks use to determine if they are on the proper course to fetch the desired mark.

Tonight I was headed towards a buoy and was surprised when I compared the gyps course to the compass course and noticed that they were about the same.
I was traveling upwind but the current and wind slippage were in opposing directions and cancelled each other out almost exactly.
Doesn't happen that neatly too often.

Hear is what I've been doing?
Hold a steady compass course for a couple of minutes and see if the heading to the mark moves.
Try to estimate the current and wind and do the trig in my head. I know some shortcuts.
Of course the simplest if you want to use the gps is to just keep the heading and course numbers the same.

I find that with the variation of wind speed and currents even in short legs of a couple miles or so it is easy to misjudge especially if the mark is upwind.

What tricks do you have both gps and non-gps?

acunningham 09-23-2011 03:32 AM

If the mark is visible and there's land behind it, watch whether the mark is moving relative to the land behind. If the mark is moving downwind, you'll make the mark, and you can even bear away to gain some speed if you're confident you won't be headed by a wind shift. If it's moving upwind, you won't make the mark unless you change something.

Classic30 09-23-2011 04:26 AM

acunningham has it right. :)

When fetching a mark upwind, I find that the GPS isn't a lot of help. It's assuming you can travel directly to the waypoint when in reality you can't. It's far better (IMHO) to keep your eyes outside the boat. ;)

One thing a GPS IS good for upwind is showing your track. If you notice your track 'bending' one way or the other you can get a good enough measure of drift to work out (a) the preferred tack to the mark and (b) where the lay-line is in real time - and nail the mark exactly.

mm2187 09-23-2011 09:08 AM

If there is not much current and the wind is steady I usually look for the mark being just shy of 90 beam of the boat. I then adjust slightly if there is current if the current is pushing me away from the mark I wait a little longer to tack and if I am going to get pushed into the mark I will go earlier.

svHyLyte 09-23-2011 10:20 AM

I do not race much any more for a number of reasons but in the day I found a hand bearing compass, a white plastic board and a grease pencil very useful. When laying a mark one can quickly determine whether the angle off the bow is steady or increasing--indicating one is low--or decreasing, indicating one is high and can bear away somewhat. If one is consistantly low but sailing one's optimum apparent wind angle/speed, mark the heading come about and sail the opposit tack until the bearing to the mark is about the last recorded heading. Mark the new heading, tack and repeat. It worked for us.

FWIW...

puddinlegs 09-23-2011 10:43 AM

Here's a fun article:

Sailboat Racing Lay Lines | Ed Broberg Photography

davidpm 09-24-2011 08:06 AM

Quote:

Originally Posted by svHyLyte (Post 778620)
If one is consistantly low but sailing one's optimum apparent wind angle/speed, mark the heading come about and sail the opposit tack until the bearing to the mark is about the last recorded heading. Mark the new heading, tack and repeat. It worked for us.

FWIW...

So there must not be any current where you are?

davidpm 09-24-2011 08:15 AM

Quote:

Originally Posted by mm2187 (Post 778602)
If there is not much current and the wind is steady I usually look for the mark being just shy of 90 beam of the boat. I then adjust slightly if there is current if the current is pushing me away from the mark I wait a little longer to tack and if I am going to get pushed into the mark I will go earlier.

That's what I do too and it seldom works out because the current and wind conspire so to mess it up.

davidpm 09-24-2011 08:18 AM

Quote:

Originally Posted by puddinlegs (Post 778642)

Very nice article, I just read it about three times.
He said.

"It is worth noting that one know of current is equal to approx. 5 knots of sailing wind and for each 1 tenth of a knot of adverse current you have to compensate in your tacking angles by at least 4 degrees of tacking angle."

Anyone care to explain that.

svHyLyte 09-24-2011 10:30 AM

Quote:

Originally Posted by davidpm (Post 779017)
So there must not be any current where you are?

There is David, quite a bit in fact, but ones bearing lines and closing-opening angles are taken from the yacht relative to the (hopefully) fixed mark hence they incorporate the yacht's relative movement. If you are your own tactician, you have to take bearings fairly often, particularly when crossing a current stream as the speed of the stream will vary relative to depth but these are nuances you will learn as your race in your own venue. For example, if you are racing on a River current tends to slacken near the banks because of shoaling while, at the same time, the wind tends to veer or back as wind always tries to cross a water/land boundary at right angles, just as waves always wash up on a beach at right angles. Hence when the mark is up-stream, an apparently longer course near shore may prove much faster than a shorter route through the stream with adverse current and less favorable wind. Likewise, if racing on a lake, reaching around the banks may prove much faster then beating a straight line across the breadth of the Lake.

Good luck...


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