This is all that is left of one of the sandglasses found on the Mary Rose.

As you can see, there is no glass left, only the wooden frame that held it.

This is a reconstruction of a sandglass. There were probably at least two different types on board the Mary Rose.

The first would be a thirty second glass, this was used for timing the speed of the ship using the log reel.

The second would be a half hour glass, used for measuring the length of the watch.