Yachting Monthly — November 2017

22 http://www.yachtingmonthly.com November 2017

It is sometimes possible to mitigate

a violent wind by finding a shoreside

feature to act as a barrier, but when

air flows round a solid object such as a

large building it usually forms eddies

and gusts. A copse of trees will often

be more effective; the vegetation does

not completely block the air flow but it

tends to comb out turbulence. In Dorset’s

Studland Bay, one of the best anchorages

on the South Coast, strong westerly winds

blow down off the Purbeck Hills but a

fringe of trees, close above the beach,

helps to soften the gusts.

A cliff or steep bluff provides more

substantial protection (Photo 5). However,

a high cliff will also induce downdraughts,

with gusts hitting the sea vertically and

then spreading out in all directions. This

is very uncomfortable for an anchored

craft, as each gust pushes it in a different

direction and the anchor cable rumbles

wildly across the sea bed. The gusts may

also combine to create a vertical eddy

(Diagram 2), so that the wind at the foot

of the cliff is blowing onshore. Choosing a

suitable spot for anchoring will be tricky

if a gale is forecast and we experienced

this dilemma a few years ago at Porth

of it is formed as a high ridge, running

SW-NE with its flanks sloping down to

the sea, and whenever Mary and I sail

past it the wind on the leeward side of

the high ground seems to be notably

stiffer close inshore. If we want speed

the conditions are superb: a dead flat sea

and loads of free horsepower. On our last

cruise, heading down the east side of the

island, we rounded Point of Ayre at the

northern tip in a NW Force 3 that held

steady in the lee of the flat plain, until

we came downwind of the hills (Photo

3). The wind then cranked up to Force 5,

reefs went into both sails and we raced

along the coast. However, later we paid

for our pleasure. After we had picked up a

visitors’ mooring buoy off Laxey Harbour,

gusts continued to roar down the slopes,

funnelling out of a small valley, and our

boat lunged and strained at its tether.

A downslope wind

screaming off the

beach in Loch Ewe

At the Isle of Man,

the stiffest winds

may be on the

leeward side

2 3

EXPERT ON BOARD How to unlock tHe secrets of winds on a weatHer sHore

Natural wind breaks

Sea

Wind under cliffs

Vertical

eddy

Gusts

Diagram 2

5

In western Ireland,
this bluff was a fairly
low barrier but gave
valuable protection
from a Force 6. The
wind had earlier
reached Force 10
PHOTOS: KEN ENDEAN