Beaufort Scale

What it does

• Small-craft limits usually sit between force 3 and force 5.
• The card pairs each force with the sea state you will actually meet.
• A separate column notes the fetch needed to build that sea.

How to use it

1. Read the gust figure, not the mean, for a go or no-go call.
2. Current against wind builds a sea two forces higher than the forecast.
3. Record the observed force beside the forecast after each leg.
4. The scale describes open water, not a sheltered estuary.

Safety notes

• A forecast force is not a guarantee of the sea you will meet.
• Turn back when the observed sea exceeds the boat, not the plan.