Geometric stag leaping into fragments

The ruler you left on the drawing board has warped from the damp, so I have been measuring the harbour wall with the back of a pencil instead. Mr Ashdown says the new chart needs the tide arcs marked true before the Lady Fenner sails, and I have not slept properly for two nights trying to make the dashed lines agree with the sandbar. Every time I get the curve right, the stag slips out from under it.

You will laugh, but it is the stag from the old tally board, the one your grandfather nailed above the chandlery door. Its antlers were always too wide for the door frame. This winter the wood split along the grain and the head came away, so I drew it again on good paper, the way it had stood there, leaping over the water. Then I could not finish the hindquarters. Every line I drew through them turned to facets, as if the animal were breaking into the angles of our sea charts.

Last Tuesday, while the fog was in, I went down to the slipway and found pieces of the original board washed up among the mussel shells, each one cut clean as a bevel. I have kept three. I am sending one with this letter so you can see that the breaks are straight and not jagged, the way wood only splits when someone has sighted along it first.

Come home before the spring tides. The stag is still leaping and I still cannot land it. Bring the good compass.

Yours, Nell