On the upper deck of the vessel, equipment is stored for use during the cruise. In the
background you can see a crane used for moving heavy objects. The other objects are
satelllite-tracked drifters that follow parcels of water and report their position
through the satellite system so oceanographers have a record of where the water and
its associated plankton have been drifting.
The satellite-tracked drifter consists of a 10 meter-long by 1
meter-diameter "holey-sock" of strong nylon cloth held open by a series of steel
hoops. The center is set at the depth where scientists want to monitor water
movements. The sock is connected by the necessary length of cable to a surface buoy
which transmits its location to the GOES satellite system. The strobe light is to
warn ships of its presence. The transponder and strobe are battery operated and can
last many weeks; because they are expensive, these drifters are usually deployed for
specific experiments and then recovered by the ship. The surface buoy has a low
profile to minimize the influence of wind on where the drifter goes.
On the aft (back) deck, Jim Manning and Bob Campbell prepare
a satellite-tracked drifter for deployment overboard.
Before
deploying a satellite-tracked drifter, cables must be stretched out to make sure they
are not tangled and that the drifter will be suspended at the correct depth.