BrianH wrote in message
...

"Steve Firth" wrote in message
.. .
Simon Brooke wrote:

and the turn
in the weather and wind direction happened within a few
minutes.

That's not uncommon, but when it happens you will see it
coming if you
know what you're looking for. Large chunks of atmosphere
moving around
fast have tremendous momentum - if they didn't they
wouldn't be

Getting a bit heated, this discussion, so I've snipped a lot of
threats and hard words!

About sudden winds.

I've lived and sailed Greek waters since 1978, and there's no
doubt that occasionally very big winds arrive without any
warning. No cloud change visible, no visibility change visible,
nothing. But it's rare.

The most common 'big fright' is the passage of a cold front, when
there will be a lot of cloud around, and if you're downwind of an
island giving shelter from the regular wind, you won't see the
roll cloud signalling the approach of the front. Suddenly the
wind shifts from the regular N segment to a southerly segment -
and that southerly wind can hit 50kts at onset then slowly drop
to 30kts. Waves will build from flat to 1metre within 15 minutes,
2 metres after about 30 minutes. By then the wind has usually
passed. Twice I've seen yachts anchored bows to a quay minced to
pieces in such circumstances, once in Levkas town, once in Tolon.

The Adriatic bora (especially in April and May) is the next most
common 'big fright'. 40kts from a consistent blue sky within a
few minutes.

After that you should consider the passing of a big cumulus. In
unstable conditions you can have lots of these, none a big
threat. Then along comes a twister. Oops! They'll flatten any
boat, drag any anchor, but they're gone in a minute and are
rarely accompanied by any swell.

Blue sky 'big frights' from the south in the Aegean are usually p
receded by a build up of a southerly swell in flat water. They're
easily the worst, but don't usually go above 30kts in summer.

There's another, interesting, blue sky fright, but it doesn't
involve a change in wind direction. It affects yachts in the lee
of some islands. When the regular meltemi goes above a certain
strength, the wind seems to accelerate down the mountain side and
suddenly there's no wind shelter. Vassiliki shows this effect
beautifully, and several Aegean islands show the effect to
dangerous levels. Calm to 50 kts offshore in seconds. Yuk.

I don't think any courses will prepare people to predict any of
these situations, though experience will raise suspicions if a
swell picks up without wind to cause it. They're all very
frightening when you first experience them, and judgement tends
to be suspended for a while. As to meeting them from a small open
boat . . .

I'm quite prepared to believe that Steve may have experienced a
weather change that frightened him immensely. I suspect the swell
may have been building up beforehand, but perhaps it's
significance hadn't registered. I think also the swell height was
exaggerated - it just doesn't build up from nothing to more than
2 metres within less than half an hour - unless you've popped
around a sheltering headland by mistake.

So, though this discussion is interesting, I think it's a red
herring concerning licencing.

JimB