Time and tide

Tides are funny things, they are irregular and prone to not following the rules. The general rule is that it is better to focus on what actually is happening rather than what should be happening. Therefore, in circumstances where there is a lot of tide and a person in the water we sometimes use this technique to get a clear understanding of what is happening real time. I give you........the tried and tested.......'bucket and fender tidal flow predicting apparatus'! It also serves the purpose of giving us a moving datum to return to.

When Columbus set sail, sophisticated men wailed,
Calling him a fool saying, "you'll topple over."
The top brains of the day said, "That can't be the way.
You know the world is flat. Think on that, foolish rover."
(Vin Garbutt)