Rick Tomlinson / Volvo Ocean Race
The final sections are likely to be dominated by small scale local effects including sea breeze and Katabatic winds, and wind shadows...
Friday 12 June 2009, 15:30 GMT
By Mark Chisnell
No scoring gates, no StealthPlays, no exclusion zones, no gate races – Leg 9 is short on man-made complexities, and there are just 525 nautical miles from Marstrand to Stockholm.
The only problem is that there’s a whole lot of real estate in the way – the fleet must pass through Oresund Sound, round the southern tip of Sweden, then leave the island of Oland to port, before a final approach to the finish at Sandhamn that also leaves the lighthouses of Almagrundet, Revengegrundet and Svangen to port. And oh, yes, there may not be much wind by the end either.
The general set-up with the weather is that a big low pressure system is slowly being pushed eastwards by a high pressure, the low crossing Sweden over the weekend and the high taking its place. While the details of timing and the specifics of wind speed and direction may vary as the forecast develops closer to the start time, this big picture is unlikely to change (even as I write that, I can feel the gift of a hostage to fortune).
Hopefully, it all means that things should get off to a brisk start, with a moderate, 10 to 15 knot north-westerly breeze for Sunday afternoon. That will send the fleet on their way, south down the Kattegat, following the south-west coast of Sweden around towards Oresund Sound, and hopefully passing under the famous bridge in the early evening.
By then, the wind is likely to have shifted further to the west, and maybe have increased a little. But the shift in direction may make conditions in the Sound lighter and more difficult. The transit of this piece of water could easily be critical, as south of the Sound it looks like the breeze will pop back up again - first one through may build a lead that’s hard to break down.
Once they clear the Sound, the westerly breeze is currently forecast to hold up on the south-east coast of Sweden overnight to Monday morning, and even into the early afternoon. So they should get across the Hanobukten and up to the island of Oland in good shape – all quick downwind miles.
But it’s just going to get lighter, and lighter, and lighter, as the high builds over Shetland and Scandinavia – which is no place for any respectable high pressure to be hanging out, even at this time of year.
The final sections are likely to be dominated by small scale local effects. And by local effects I mean everything from the sea breezes and Katabatic or drainage winds we’ve seen elsewhere, to the wind shadows, channelling and acceleration of the breeze caused by islands and mainland shores alike.
And to be honest, beyond Oresund Sound, I have absolutely no idea where, what or which of these potential local effects is going to be important. So I’m going to leave this Preview as short and simple as the leg itself. We’ll just have to see how it plays out on the day.
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