Storm Doris and Channel Sailors

[boatman61]

A shot of the 'Race' on a quiet day.. and another of a yacht caught in the Race..
One of many along the S coast UK.. this is off Portland Bill.
Now imagine that in a F8+ wind against the tide.

[Dockhead]

Originally Posted by moseriw

Just a dumb question to the audiance. I had 61 knots gusts in a force elven at the mediterranean and in a mistral . right south between mallorca and sardinia. Course strait Cabo de Gata Spain to Northern Sicily.

Well OK it was rough with waves upto 24 ft. but we always felt comfortable on my 47 ft Vagabond Blue Water Cruiser, longkeel with 20 tons on the hook.

What is the problem in teh channel? The tide and shallow water (short steep waves) or what else?

Thank you for qualified input - willing to learn...

Well, first of all, a 61 knot gust is not a F11! Beaufort forces are based on sustained mean wind speeds which go on long enough and over a long enough distance (fetch) to impart energy to the sea surface. Sudden squalls, other short term weather events, and certainly not gusts, of a given speed, don't amount to a corresponding Beaufort force.

Wind is not what causes problems -- it's sea state. It takes time and fetch for a given wind speed to create a dangerous sea state. A real F11 in the open ocean will produce waves of 11.5 meters and up to 16 meters, with overhanging, breaking, crests. Actually a well developed wave train formed over a large stretch of open ocean may have dangerous breaking crests already at F9. My boat was knocked down by a huge breaking wave in a F9 in the North Sea, a couple of years ago.

The Channel is a challenging place to sail in terms of sea state because the prevailing Westerly weather can develop over several thousand miles of open ocean. Add tidal currents which run up to 12 knots in places, and you can have deadly conditions -- conditions which can sink ships as well as smash our little boats -- already at F8. If you want to die, just try to sail out the Needles Channel in a SW F8 blowing against the ebb during a spring tide. Or try the tidal race at Portland Bill in similar conditions.

But the Channel is actually nothing compared to the sea area West of Ireland and Scotland -- the Western Approaches. This is where the wave energy formed over the whole Atlantic Ocean peaks, and has the highest significant wave heights in the Northern Hemisphere.


The Med, on the other hand, is not the ocean. It is an enclosed body of water which doesn't have enough fetch to develop ocean waves, and which has weather which is dominated by short-term land effects (like the Mistral etc.). It's actually challenging in its own way, as the waves tend to be short but viciously steep in bad weather. But there are no real ocean sea states there. IIRC, the all time record for a high wave on the Mediterranean coast of Spain is something like 7 meters, and the 95th percentile wave in the Med is something like 2.1 meters. The ocean is very different from this.


Read up about the '79 Fastnet storm disaster, to get a taste for what the sea can be like over here. That was a Force 10. 25% of the yachts participating were rolled, 24 were abandoned, and 5 were sunk. 15 sailors were killed.

[markpierce]

Good time to tighten-down the dogs on doors and hatches.

[Hoofsmit]

Originally Posted by boatman61

A shot of the 'Race' on a quiet day.. and another of a yacht caught in the Race..
One of many along the S coast UK.. this is off Portland Bill.
Now imagine that in a F8+ wind against the tide.

Great photos, it always amazes me how the inner route can be so calm, done it a few times in mv's !
I go 8Nm off when under sail ! That race wonders around a bit to much for my liking

Dockhead .... great summary, I think also that the guessing of when and where that ' low will go' and whether a secondary front is going to grow is always a channel sailors fear

We have it so much easier with weather forecasts than those that went before.

[Dockhead]

Originally Posted by Hoofsmit

Great photos, it always amazes me how the inner route can be so calm, done it a few times in mv's !
I go 8Nm off when under sail ! That race wonders around a bit to much for my liking . . .

The Portland Race is like a living entity. It looks surrealistic at peak flow at springs. I have passed it both inside and well offshore. The inside way can be quite terrifying, as the race can nearly reach the beach. As you say, it wanders around. In any kind of weather, I stand off well offshore.

The Race ate a commercial fishing vessel with loss of life, a few years ago. It is not to be trifled with.

[moseriw]

Dockhead:
But there are no real ocean sea states there. IIRC, the all time record for a high wave on the Mediterranean coast of Spain is something like 7 meters, and the 95th percentile wave in the Med is something like 2.1 meters. The ocean is very different from this.

OK I had the feeling be'd had 7-8m waveheigth. You said now way all time high is 7m - which we definitivly have not had.

Though I did a little research and grabbed out this:

The climatology of the Mediterranean SeaEnclosed between the storm belt of northern Europe and the
tropical area of northern Africa, the Mediterranean Sea has a
relatively mild climate on the average, but substantial storms
are possible, usually in the six month winter. Cavaleri et
al. (1991) provide a clear description of the situation. The
maximum measured significant wave height reach 10 m, but
model estimates for some non-documented storms suggest
much larger values. Even in the relatively small Adriatic Sea
the oceanographic tower of ISMAR (Cavaleri, 2000), located
on 16 m of depth, suffered heavy damage till 9 m above the
mean sea level.

The wind and wave atlas of the Mediterranean Sea –
the calibration phase

source: http://www.adv-geosci.net/2/255/2005...2-255-2005.pdf