@prefix cpm: . @prefix dc: . @prefix dcat: . @prefix dce: . @prefix dct: . @prefix grg: . @prefix iop: . @prefix ns0: . @prefix ns1: . @prefix owl: . @prefix pav: . @prefix prov: . @prefix puv: . @prefix qudt: . @prefix rdf: . @prefix rdfs: . @prefix reg: . @prefix semapv: . @prefix skos: . @prefix sssom: . @prefix void: . skos:altLabel "NOC spar buoy" ; skos:definition "A custom-built spar buoy platform designed to measure waves, wave breaking and whitecaps in-situ using capacitance wave wires. The main body of the buoy consists of two sealed sections of aluminium alloy tubing, with the lower section being 6 m long and 25 cm in diameter, and the upper section being 4 m long and 10 cm in diameter. The wave wires are mounted along the upper section and the buoy is ballasted so that the wires are half submerged, on average. A sealed dome is mounted at the top of the buoy, and this contains the cameras, buoy motion sensors, and electronics for the wave wires. The acoustic and optical systems are distributed along the length of the submerged sections, and have separate electronics housing near the base of the buoy. At the bottom of the spar are two hexagonal damping plates that act to increase the natural period of oscillation of the spar to about 30 s. The buoy has an overall length of 11 m and, including all instrumentation, a total weight in air of approximately 440 kg. It can carry enough batteries to operate for 5 days at a time."@en ; skos:notation "SDN:B76::B7600015" ; skos:note "accepted"@en ; skos:prefLabel "National Oceanography Centre [standard] spar buoy"@en . skos:member .