Cruise inventory

RRS John Murray JM6/75

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS John Murray (74MJ)
Cruise identifierJM6/75
Cruise period1975-04-18 — 1975-05-06
StatusCompleted
Port of departureLowestoft, United Kingdom
Port of returnLowestoft, United Kingdom
Objectives1) To lay six Plessey self-recording current meter rigs, five on the seaward side of the Sizewell- Dunwich bank and one inshore from the bank. To monitor continually current velocity and direction at midwater level to provide input data for a mathematical model and for the field study itself. To recover the six moorings at the end of the cruise.

2) To supplement the geophysical survey begun on cruise 2/75 of the RV Edward Forbes, Feburary 1975, where data was either incomplete or of poor quality.

3) To undertake diver inspection of the current meter rigs as soon as possible after mooring to ascertain they are moored correctly, whether the meters are functioning, and to photograph the rigs on the seabed. To repeat this inspection at the end of the cruise immediately prior recovery of the meters. If conditions permit, to examine the topography and lithiology of selected areas of the seabed.

4) To sample the seabed adjacent to the Sizewell- Dunwich bank, firstly with a van Veen grab to give an approximate idea of sediment distribution on the seabed. To use this to provide a basis for sampling with a Reineck box corer, these samples to be returned to the Taunton Laboratory for subsequent detailed analysis.
Chief scientistBarbara J Lees (Institute of Oceanographic Sciences Taunton)
Cruise reportRRS John Murray JM6/75 cruise report john_murray6_75.pdf — access key 'C' (0.42 MB) 
Ocean/sea areas 
GeneralNorth Sea
Measurements 
Physical oceanography 
Current metersQuantity: number of deployments = 6
Description: Current meters deployed and recovered; 12 days.
Geology and geophysics 
GrabQuantity: number of stations = 40
Core - soft bottomDescription: physical analysis of sediments;paleontology
Single-beam echosounding
Single channel seismic reflectionQuantity: track kilometres = 180