Gallery: Boat / The knot log Walker's ...

The knot log Walker's "Knotmaster" log, Mark III A, made in England by Thos. Walker & Son Ltd., 58, Oxford Street, Birmingham, B5 5NX. This is a time-honoured device for measuring distance travelled. You tow one of the impellers (seen here in the box lid) behind the meter, which clamps onto the stern of the boat; as the impeller turns, it turns the meter (via its towing line) which clocks up the miles. The dials are (left, right, and main) tenths, units, and tens of nautical miles, up to 100 miles (presumably the navigator will remember to check it at least that often. or be thrown overboard).