How the weather can block my progress

posted 4 Aug 2015, 11:17 by Dominic Thwaites

It may seem strange to some that the wind can so effectively put up a barrier. After all, I can tack can’t I? So I thought I’d explain the current situation.

I’m in Fishguard (North side of the Southern Welsh peninsula - The Pembrokeshire Peninsula) and I need to sail South. It’s too far all the way across the Bristol channel from here so I just need to get to the South side of this peninsula; A hoop-like trip of about 40 miles. Not far. But I can’t for 3 days. Why?

This peninsula has very strong tides around it. So I have no choice but to go when the tide is with me. But the winds are against me. That makes the wind going in the opposite direction to the tide. Which makes the waves go the opposite direction to the moving water. Which dramatically shortens the wave length causing very “steep” seas. Sailing or motoring against the wind and waves in such conditions is a horrible, bucking bronco, buckets-of-water-in-your-face experience that can be quite dangerous.

Apart from the wind, changes in depth can cause some pretty nasty surface dynamics as the water moves over the sea bottom. Which just adds to the misery.  

If there were no water movement contra winds would not necessarily stop me. Or if there was less wind (or winds with me) then I’d gladly let the tide take me along. It so happens, in this case, that you can navigate around most of the nastiness due to changes in depth.

The Pembrokeshire peninsula has an additional interesting feature. Lots of rocks and little islands. There are two particular islands North and South, which squeeze the water between them and the mainland such that the tide in there are really fast - 8 or 9 knots even. I could go outside these islands for less of a sleigh ride, but the tides are still strong and the waters are open to the North atlantic. So, actually, going inside the islands (despite dire warnings of fast tides) is the easier option. Alas, both routes are untenable with these winds.

There’s a wretched low pressure system idling along to the west of Ireland causing all this unpleasantness. Quite apart from all the above there are gale force winds forecast all over the place. So no, I have to stay put! It’ll be over by Thursday.