🌊 Tidal Window & Crossing Planner

Two kinds of people watch the tide: sailors who need enough water under the keel, and everyone crossing a causeway, ford or sandbar who needs the water gone. Give it one high water and one low water from any almanac and it builds the curve, marks your safe window to the minute, and shows how badly the old rule of twelfths would have misled you.

High water time

High water height (m above chart datum)

Low water time

Low water height (m)

What are you doing?

Floating — I need water Crossing — I need it dry

Charted depth at the spot (m)

Your draught (m)

Safety margin (m)

Time the crossing takes (minutes)

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