Tactical 'Pop' Quiz

Originally posted by Roy Race Can you clarify whether you would do the lee-bow tack early or late or both?

Personally I'd always go for the lee bow tack first, wether it was left or
right for the reasons I made earlier (you never know how things will pan
out later in the beat). (Even more important if the tide is going right to
left for example simply because with the majority of the fleet on
starboard, manage to get out the back door right early, nine times out of
ten you'll nail them simply because the starboard nature of the majority
forces them way down tide and they over stand on the way back.)

Originally posted by Roy Race What if there's a favourable shift right at the start?

I might well ignore it, depending on my calculations regarding the start
line length, course length and time duration and how much left to right
tide I'd be expecting. A favorable shift (lift at the start)could see you
massively over standing if you were already at the pin end.. Alternatively
a genuine favorable shift which of course I take to mean a massive header
shortly after the start with me down the Port End I wouldn't obviously
ignore and would probably knock the tide off the lee bow anyway, that I
couldn't ignore.

Originally posted by Roy Race What's a "final run"?

The last 25 % of the course give or take. How can you totally qualify it?
For that course my strategy would have been to try for..
First 25 % Left, mid 50% middle and left but trending ever right, and final
approach right, and short of the lay line getting lifted by the tide.

But of course events can occurr, but overiding everything the
fundamental rule is always Take the tack that's taking you closest the
mark and if the tide is assisting that tack all the better.

Edited by G.R.F.

Er...

This could develop into a full blown chapter.

I always maintain it does matter.

Take the lee bow early and only the weather bow on favorable shifts.


I also always used to suggest the length of the startline is very important
and how far down tide the favored end might be in relation to the time
duration of the beat.

Depending on those calculations, is how long you get to stay on the
favored tack, enhanced by how far down tide of the start line you position
yourself at the gun. Extreme circumstances can produce a one tack beat
when the wind has dropped for example and all the boats from the none
favored end sailing high and relatively fast lay the mark bang on whereas
those at the favored end find themselves having to free off further and
further going slower and slower with the same effect of being the wrong
end of a 'knock'. Extreme, but it makes the point and has happened to me
over the years enough times to cover for.

Yes you should consider the tide as a conveyor belt and everyones
position relative to each other remains equal, but factor in time and
reduced wind and some can find themselves more 'equal' than others in
relation to fixed mark positions has often been my experience as has
travelling faster earlier rather than having to pay catch up later..

Edited by G.R.F.

Absolutely.

Another layer to this should be that you need a good
reason NOT to do the longest tack first. In this case,
if the w/w mark is dead upwind (true wind) and the tide
is flowing l to r, then starboard becomes the long tack.
Doing your short tack first quickly narrows your options
and puts you into a corner.

But yes, if wind and tide are constant up the course,
you have to do both tacks and it doesn't matter which
order you do them in.

Of course, wind and tide are very rarely constant up the
whole length of the course!


Edit: Oh, I see! Tack'ho was replying to GRF, not me!
Yes, what he said.




Edited by Roy Race

Arrrhhh, you see there's the confusion that's simple vector logic.  now if the tide and wind were equal all the way acroos the race course it wouldn't matter which way you went, cause assuming everybody hit the layline and went the same speed it would be irrelevant (you'd spend the same time on each tack regardless of the order you did them).  What I believe your saying is you need to be on the appropriate tack at the appropriate time to suit the variances in wind and tide across the course.

ie. minimise your time on the bad tack and maximise on good!

Well it's always a difficult one, and I've never seen a definitive calculation
written, but as a rule of thumb, lets say 8knots wind and 4 knots tide left
to right.

So your sail is being driven by 8 knots true and then whatever created
wind your particular craft is capable of which produced the apparent wind
your sailing on.

So basically going one way a percentage probably 50% of the tides speed
providing your bow gets a sufficient angle against it assists the 'created
element of the wind that produces the apparent wind and going the
opposite way, it degrades it. So the boat travels not only physically faster
through the water that is flowing say 10 knots of combined speed 8 from
the airspeed and two from the tide and 6 knots air speed the other way,
and because the created element of the wind is stronger one way it also
enables the boat to appear to point higher, whilst not being able to point
as high on the opposite tack. (I'm guessing at what level the speed of
current contributes, it would vary according to the precis angle it lifts the
foil at I guess 50% at 45 degrees no doubt some maths head could
elaborate.)

Anyway, maybe it's more noticeable for us on Boards (the displacement
speed type), but it's been my experience that it most certainly has a
similar effect on the boats I've sailed to date.

It needs sketches and angles to explain thoroughly, I'm available for
lecture tours (that's a joke, me lecturing dinghy sailors could you
imagine it ) Eric Twiname covered it I'm fairly sure in Start to Win..

Edited by G.R.F.