The traditional log ship takes some carpentry but there are simpler alternatives. A bucket is great but is the devil to haul in. Small plastic beakers, filler funnels, mugs, and even empty cans work just as well, providing you use a light line and they are easy to recover. Even a bottle partly filled with seawater works.

Drill a hole near the lip of the can or beaker and drill another very small hole in the base to prevent trapped air bringing it to the surface and allowing it to skip along. A weight on the log line a few inches from the lip pulls it underwater, and another a few feet further back helps keep it down.

Allow 6 metres or so (20 feet) of slack before tying the first knot. If you tie one knot every 14.5 metres (47 feet 3 inches) you need around 122 metres (400 feet) of line to measure eight knots. If you do not have enough line then reduce the interval between knots to reduce the time. The spacing of knots is determined by

Space between knots = 1.6878 x the timing interval

If you cut the time from 28 to six seconds then the knots are spaced at 3 metres (10.13 feet). After allowing for the spare line this takes about 31 metres (100 feet) of line.

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