SEAMANSHIP
Why sailing round the
island makes sense
Forget the racing aspect. This annual ‘jolly’ is an ideal way
to sharpen up your weather skills and improve your sail
handling. Chris Tibbs explains what’s involved.
B
efore you start, it’s with the dominant direction confidence in the forecast than coastal waters. This is a
vital to study the tides, southwesterly. So, in the if expectations keep changing. thermal effect and can give
because using the tidal absence of any depressions We’re looking at the tracks of a light offshore breeze first
streams can make a huge tracking across the south of depressions and the positions thing in the morning. For
difference to the outcome and England, we can expect a of highs. The steadier they the wind to get going again
knowing when to go into the light wind start with the wind stay, the better it is. we need the land to heat and
tide or try to dodge out of the building through the afternoon We can split the weather generate turbulence. This is
main stream will significantly from the southwest, before into three parts: large scale most easily seen when small
change your final position. dropping during the evening synoptic features and the track cumulus clouds develop over
Sailing around in what’s and going calm at night. during the day, the thermal the land. There is, therefore,
described (loosely) as a 55M By mid June, we expect effects caused by the land an advantage for the cruising
circle will give a variety of to have reasonably settled heating during the day and class starting after the racing
wind angles and should test weather without large Atlantic how the land funnels the wind class, because the start should
each point of sail. However, depressions spoiling the day. or shelters the racecourse. be in stronger wind.
even if the wind is in a steady However, it’s important to A race around the island For a classic Round the
direction there will be places follow the synoptic systems brings the synoptic situation, Island race we need an early
where it’s accelerated or during the week beforehand to thermal and mechanical effects but light southwesterly, which
slowed by the land. There will see if it’s true. By doing that together and helps to explain indicates that the wind will
also be changes during the we get a feel for the weather why the wind can be so varied increase from this direction
day caused by the heating and and what it’s likely to do or on different parts of the course. through the day, peaking mid
cooling of the land. how it may change. If the to late afternoon.
During June, long term forecasts stay steady, and by Light at night How far the wind increases
averages show that the wind this I mean that the forecast On most nights, unless there’s will depend on the synoptic
direction is usually between for Saturday remains similar an active depression, the system and how close the
west and south for a little throughout the week, then we wind drops over the land isobars are together.
over 50 per cent of the time, can have a great deal more and this spreads out over Although coming from the
right direction, this isn’t really
a sea breeze but a mixture
of the wind generated by the
synoptic situation helped by
the warming land. As such, it
may increase to 20 or even 25
knots (Force 5 or 6) as it gets
funnelled through the Solent
and depends upon how active
any depression is.
If there are no depressions
to worry about, we may get
a true sea breeze. For that
to develop we need widely
spaced isobars and a very
gentle early morning wind.
The best time for a sea breeze
to develop is when the early
morning breeze is from the
northwest. As the land heats
to a greater temperature than
Round the Island Race: A colourful start but, in this case, with an unusual easterly wind direction.
the sea we get a period of calm
108 Sailing Today July 09
ST147 Wclass
RTG.indd 102 13/5/09 13:42:17
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148