12/10/2026
How do you navigate a ship when there are no charts, no GPS and it’s the middle of the night?
This remarkable Tudor tide calculator, recovered from the Mary Rose, helped the ship’s pilot estimate when high tide would occur by taking a bearing on the Moon.
That information could be vital when sailing around the south coast of England, where strong tidal changes and narrow waterways made timing the tides a matter of real importance.
Even more fascinating, the calculator’s markings were designed so they could be felt by touch—meaning a navigator could use it in darkness without needing to see it.
A tiny object revealing just how skilled and resourceful Tudor sailors had to be.
Would you have trusted your navigation skills and the Moon to find your way home?