A wave staff to be anchored at sea and containing sensing and telemetering equipment is described. This gives a record at the land station of water level changes due to tides and of waves as they pass the staff. The staff is a 13 metre long PCV tube

the upper half comprising a capacitance with inner plate a foil layer

dielectric the tube wall

and outer electrode the sea. Wave direction is obtained by a separate device comprising a raft moored near to the staff. The raft streams behind its mooring and substantially points into the advancing waves and changes its slope as these pass under it. This slope and its direction referred to magnetic north

are telemetered to the land station to give the direction from which the waves arrive.