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Shaun Van Poecke Shaun Van Poecke is offline
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First recorded activity by BoatBanter: Dec 2006
Posts: 146
Default Estimating Leeway


"Wilbur Hubbard" wrote in message
...
When you estimate leeway you end up plotting it on a chart, don't you?
That should tell you something. On a chart there's no apparent wind
and there's no apparent current. There is only true wind and true
current as it applies to the chart.

If you used apparent wind/current you'd have to extrapolate to true
prior to placing yourself on the chart. So why bother?

Leeway is a function of true wind and current when it comes to plotting
your position on a chart. Apparent is totally meaningless because you
have to ask yourself the burning question: apparent to what? Your ship,
of course. What you feel from the deck of your ship means nothing
as concerns your geographical position (GP)


Wilbur Hubbard


Im not so sure about that... leeway can be estimated on many levels....
the fellow out in a motor dinghy, another guy out in a sailing dinghy, and
the person out in a larger yacht with navigation instruments on board.
estimating leeway in a harbour is entirely a different matter from
estimating it in the open ocean. leeway is also something that varies a lot
with the type of vessel.

I know when im out sailing in sydney harbour on my beach cat, i suffer
leeway a lot, but i can eye it in off a landmark to allow for my course. I
know in relaity i will be lucky to end up with a course made good within 30
degrees of what i was helming for!

Out on my 26 foot keeler leeway is a lot less, but on a longer trip.... it
sure can add up to a lot! If im out of sight of land it gets to be
impossible for me to estimate in my head and then its time to compare on a
chart my GPS course vs. compass steered course. It would take a very
experienced and/or lucky person to be able to estimate leeway on a vessel
they were unfamiliar with in waters that were unknown to them.

Shaun