SMALL-BOAT SERIES PART 4

In a world of digital mapping, there is still room for sea charts and the wealth of knowledge they offer to anglers

A simple secret is revealed.

How sea charts can improve your angling success.

M   neglect to carry or even use one a marine chart because they rely on electronic plotters, but if you become too reliant on technology you run the risk of coming unstuck if those gadgets develop a fault. Apart from being an essential aid to navigation, a sea chart is one of the most useful tools in a dinghy angler’s armoury. ese maps are invaluable for helping to locate likely marks for the various species of fish found in the area you are fishing.

A large-scale chart of the area you are fishing has a mass of useful information to help you locate and catch fish, including the precise location and nature of banks and reefs, isolated depressions, tide rips, wrecks and even the composition of the seabed.

NUMBERS GAME

A quick glance over the chart will reveal a mass of numbers and contour lines. ese indicate depths or soundings in metres, again reduced to chart datum. At the point where you see a number 14, the chart is telling you that at low water on the largest astronomically predictable spring tide there will be 14 metres of water. A second smaller number is printed alongside the larger number (right), this indicates a fraction of a metre, for example 146 indicates that at chart datum the depth at that point is 14.6 metres. Underlined numbers, typically found on the green inter-tidal zones, indicate drying heights. For example, 24 if underlined indicates a drying bank or reef with a height of 2.4 metres above the water level at chart datum.

Tidal heights printed in tide books are given as being the height of the tide above chart datum, and usually both the height of high and low water is given. You should use a tide book giving heights at the nearest port in the area you are fishing. I use tide books for Swansea, Cardiff or Newport. When a tide book provides a height at high water of 13.6 metres at a point indicated on the chart as 2.3 metres, the water depth at high water would be 15.9 metres. At low water the height given could be 5.5 metres, so now the height at that same point now would be 7.8 metres.

SEABED TYPES

Study your chart further and you will come across groups of letters or individual letters indicating the type of seabed. For example, if you saw an area marked M.Sh.G.P, that would tell you the bottom consisted of a mix of mud, shells, gravel and pebbles, great ground for thornback rays, for example. R.Sh.Wd indicates a bottom consisting of rock, shells and weed, hard ground over which you might encounter smoothhounds, bass or pollack As you become more familiar with your chart you will be able to locate isolated banks and subtle depressions in the seabed. Typically, such marks are good fish-holding ground where, depending on where in the country you are, bass, turbot or blonde rays might be found.