Next message: (no name): "Re: lv-ab: Heaving-to ... thanks for the input"
In a message dated 10/10/2005 12:48:00 GMT Daylight Time,
writes:
OK .. If you say you're calm, then you're calm. Remind me not to ask you any
questions when you are pissed off at something ;-)
RARELY get pissed of at anything though i do find it strange that people
post rubbish pretending it is factual as i am sure there are a lot of people
here trying to learn and you cant get leeway from a GPS so lets not confuse
things for them.
The most basic handheld GPS has SOG, COG and X-trak Assuming there was a 'go
to' target punched into the GPS (wouldn't that be normal?) and assuming the
boat has a compass at the helm (normal again?) you would have drift, leeway,
whatever you want to call it, two ways.
OK this has gone on a bit now :-(
BUT lets fantasise a bit - you have an eventual destination programmed into
your GPS that would be the basic starting point
assuming your destination is direct to windward at the start of your three
day two nights 250 mile journey
it would seem reasonable to insert quite a few waypoints on either side of
the direct course to the destination - we can call them turning points - and
when we reach them we change tack
assuming unlimited sea room we can place them at distances equal to boat
speed x hours
lets assume for simplicity 5 knots boat speed and either 4, 6 or 8 hours on
the one tack
so we have way/turning points with 20, 30 and 40 mile legs
now depending on our boat the tacking angles could be 85 - 110 degrees
so before we start we plot these positions on our chart then program them
into the GPS
assuming no tidal flow
we arrive at the first mark and it is to windward we are below the turning
mark by X miles
is that leeway?
i would say not necessary but leeway could play a part there
NOW if we are above the mark do tell me what are you going to call that?
apart from BLOODY GOOD SAILING ;-)
As far as i am concerned leeway is tied to the boat and will vary with keel
style and draft, sails set, sail trim, boat trim, wind strength and sea
state.
'Leeway' is not ending up to leeward of your destination but the difference
between the heading and the track angles.
To accurately calculate leeway you are looking at coupled instruments with
some decent computing power. You need to be looking at wind direction and
boat heading and CMG ALL at the same time.
Then unless you are sailing on a piece of water with no current flow tidal
or wind driven you need to factor that in too.
EONGUH
regards
David
___________________________________________________________________________
|| The Live-Aboard List : send a "subscribe" or "unsubscribe" request ||
|| in body of message to: ||
