Today we are encountering a rather rough sea. Work had to stop. It is impossible to put any measuring instruments in the water ... the winch cable would have to bear too much pressure and the instrument might bang on the hull.
The Beaufort scale of wind force is an empirical measure that relates wind speed to observed conditions at sea or land.
This scale was devised by Sir Francis Beaufort in the year 1806 for use in vessels of the Royal Navy. It was adapted in 1874 and in 1939 the International Meteorological Organisation (now WMO) agreed to the use of a sea criterion by which the wind force was judged from the appearance of the sea surface.
Force 8 on the Beaufort scale corresponds to a gale, winds of 34-40 knots (62-74 km/h) and moderately high waves with breaking crests forming spindrift, well-marked steaks of foam blown along in the wind direction and considerable airborne spray.
Seasickness pills are quite fashionable today!