It's pretty much the same as a chip log, isn't it.

Usually made of wood but can be anything that floats.

Drop the log at the bow and count how much time it takes
to get to the stern and the time it takes. Knowing the length
of the vessel and the time can yield the speed through the water.

Some of these chip logs even had a line attached for retrieval.
Some were expendable. Since the Dutch are known for frugality,
their logs were probably retrievable.

CN



"Joe" wrote in message oups.com...
Question:

What is a Dutchman's Log?

What is it made of?

How is it used?

Joe