What the Tide Tables Taught Me About Planning
The first time I went rock-pooling with a tide table, I felt slightly ridiculous. It’s a little printed booklet of times and heights, the kind of thing that seems to belong to fishermen and harbour masters, not someone who wants to look at crabs on a Sunday. But it changed the way I think about planning almost everything.
The sea is punctual
Tides are one of the most predictable things in nature. They rise and fall twice a day, driven by the pull of the moon and the sun, and they can be calculated years in advance. If the table says low water is at twenty past two, the sea will be at its lowest at twenty past two, whatever you had planned.
That predictability is the whole point. You can’t move the tide, but you can know exactly when it will turn, and plan around it.
Plan backwards from what you can’t change
Rock-pooling taught me to start with the fixed point and work backwards. If low water is at twenty past two, the best pools are open for about an hour either side. That means arriving at half past one, leaving home at one, and having lunch early. Everything else bends around the one thing that won’t.
Most plans go wrong because we start from what we want to do and hope the world fits around it. The tide table reverses that. It asks what won’t move, and then fits everything else into the gaps.
Leave before you have to
The most important rule of the shore is to watch the water, not the clock. A rising tide can cut off a beach or a sandbar far faster than you expect, and the safe time to leave is well before the water reaches you. Experienced walkers turn back early, while the way home is still easy.
I’ve found the same is true of deadlines. The moment to change course is when things first start to slip, not when the water is already around your ankles.
Small margins add up
Tide heights vary from day to day, and the biggest tides come around the new and full moon. On those days, the sea goes out further and comes in faster. A plan that works with an hour to spare on an ordinary day might work with ten minutes to spare on a big one.
It’s a useful reminder that the same plan isn’t equally safe every day. Building in a margin isn’t pessimism. It’s just reading the table properly.
Updated
Since I first wrote this, a few readers have asked where to find tide tables. Most coastguard and harbour authorities publish them for free, and many weather services include them alongside the forecast. Whichever you use, check that it’s for the right stretch of coast, as times can differ by an hour or more between nearby harbours.