The east coast of England is one of those sailing areas where you often wish that your yacht came equipped with an under carriage. Whilst we are blessed with a rich and varied area to sail in, much of it is inaccessible if the tide isn't high. Several rivers have bars at their entrances and many marinas and landing places become seas of mud instead of water once the tide has ebbed. All of which means that calculating tidal heights and times becomes a matter of great importance, especially to those of us who are dim enough to drag a 6ft keel around such a coast.

Pete Widders aims to make our lives just that bit easier, he has come up with the Tidal Slate -a device to make finding the time and height of the tide at a secondary port (no groaning you at the back!) simpler. The great virtue of this device is that you get everything you need, bar the tide table, on one laminated sheet. The slate has a wheel on each side, one for tide height, the other for tide time, and the standard curve for the relevant port underneath. There are boxes to fill in and instructions on how to do it. A separate sheet of instructions comes with the slate and I had the tide tables for Walton-on-the-Naze and a chinagraph pencil to hand as well. All the data is from the admiralty, as is the method of calculating heights and times.

The wheel in use calculating heights for Bradwell, again there is a larger version

Using the wheels and slate the actual calculation is a simple affair, so long as you read the instructions and don't try to jump ahead of yourself. Just look up the values on the appropriate wheel and fill in the boxes as directed, then draw the lines on the standard curve as per usual, if you make a mistake just wipe it off with your thumb. The big advantage comes from it all being in one place, the laminated tables can be joined to the slate with a piece of string through the brass eyes provided -as could the pencil for that matter. As the slate is laminated it is safe to take into the cockpit, and it is of course reusable year after year, with only a new set of tables (£1.95) being needed.

For my sailing area I would need two or three slates, the one to the South (Whitaker Beacon to Sunk Head £24.95) extends as far as the Crouch and Roach and to the North I would need both the Felixstowe Pier to Iken Cliffs(£19.95) and the Orfordness to Winterton-on-Sea(£24.95) wheels. This seems a little expensive, but if you find that you don't need an almanac each year the you would soon start to make savings. Pete also makes the point that there are no electronics involved, and speaking as a man whose depth sounder and GPS are both on the blink, this has a distinct appeal. You will have to take a little care of the slates as the laminated construction isn't that tough, but if you look after them they should last you several years.