The operational cycle goes like this. Each of the floats is dropped in the ocean from a boat at a set point and activated from a satellite. Then the float immediately sinks about 2,000 metres. That's two whole kilometres down in the water. It stays at this depth for about ten days and is carried around by the currents which operate in the ocean at this level. During this time it's possible for it to cover quite large distances but the average is 50 kilometres. So what is it actually recording? Well at this stage nothing, but as it rises to the surface it collects all sorts of data, most importantly variations in salinity, that's salt levels, and the changes in temperature, a bit like underwater weather balloons. Then when it gets back to the surface all the data it's collected is beamed up to the satellite. After about five hours on the surface the float automatically sinks, beginning the whole process again. What happens to the data? Well the information is transferred direct to onshore meteorological stations, like our one in Hobart, and within four hours the findings can be on computers and they can be mapped and analysed.