Cruise inventory

FRV Explorer 4A/73

Cruise summary report

Cruise Info. 
Ship name (ship code)FRV Explorer (74EX)
Cruise identifier4A/73
Cruise period1973-04-18 — 1973-05-07
Port of departureAberdeen, United Kingdom
Port of returnLeith, United Kingdom
Objectives1) To establish current meter moorings in the Fair Isle area and central Northern North Sea and to recover at the end of the cruise
2) To monitor temperature, salinity and plankton distributions in the mooring areas
3) To make additional current measurements using parachute drogues
4) To make continuous surface temperature, salinity and chlorophyll measurements and plankton sampling along the 150 m path between the 2 mooring areas
5) To carry out trials on moorings in 1000 m depth to the north of Shetland
6) To collect water samples in selected areas for heavy metal analysis
7) To establish a current meter mooring near the Isle of May at the end of the cruise

The 7 current meter moorings were deployed after some delay due to unsuitable weather. The programme of hydrographic stations had to be cancelled due to the breakdown of both hydrographic winches, an alternative parachute drogue tracking programme was carried out instead. Bad weather on the 29/04/1973 prevented further stations from being worked and surface surveys for temperature and salinity were affected.

Explorer docked in Aberdeen on the 29/04/1973 till the 02/05/1973 so both hydrographic winches could be repaired and for a change in personnel. The generator crankshaft was ruptured on passage to the Isle of May and ''Explorer'' was forced to go to Leith for repair on the 07/05/1973. RV Clione recovered the North Sea moorings on the 30/05/1975 and on the 01/06/1973.
Chief scientistHarry D Dooley (Department of Agriculture and Fisheries for Scotland Aberdeen Marine Laboratory)
Cruise reportFRV Explorer 4A/73 cruise report explorer4_73.pdf — access key 'C' (0.10 MB) 
Ocean/sea areas 
GeneralNorth Sea
North East Atlantic Ocean (limit 40W)
SpecificFair Isle, central Northern North Sea, north of Shetland, Isle of May
Physical oceanography 
Water bottle stationsQuantity: number of stations = 48
Current metersQuantity: number of deployments = 7
Surface drifters/drifting buoysDescription: drogues
Chemical oceanography 
PhosphateQuantity: number of stations = 12
NitrateQuantity: number of stations = 12
Total - NQuantity: number of stations = 16
SilicateQuantity: number of stations = 12
Trace elementsQuantity: number of stations = 10
Description: metals
Biology and fisheries 
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of stations = 32
Description: chlorophyll and phaeophytin
Particulate organic matter (inc POC, PON)Quantity: number of stations = 17
Description: organic carbon
ZooplanktonQuantity: number of stations = 26