Tide Table

The trust wanted something maritime, which is a request that usually ends in a badly drawn boat. What they had, in a filing cabinet, was a hundred and forty years of tide records for their own harbour.

The window is one calendar year of predicted tide at Ardross — 2023 — drawn as a curve, one panel per fortnight across three lights. The lead is the curve. Where the tide runs high the lead swings wide and the glass between it is pale; at neaps the lead pulls together and the glass darkens.

Six millimetre came

A tide curve does not have straight lines in it. Standard nine-and-a-half millimetre came will take a gentle curve but it fights you on a tight one, and there are places in panel 13 where the curve turns inside a hundred millimetres. Those runs are six millimetre, which is the narrowest we will use in a window that has to survive weather, and they are backed by the saddle bar rather than crossing it.

Reading it

There is a brass plate under the sill with the year, the datum and the source of the predictions. Most people who come into that room see a blue window with a wave in it. Two or three a year work out what they are looking at, and those two or three are why it was worth doing.