Cruise inventory

RV Sarsia 15/75

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Sarsia (74SR)
Cruise identifier15/75
Cruise period1975-05-27 — 1975-06-05
Port of departurePlymouth, United Kingdom
Port of returnPlymouth, United Kingdom
ObjectivesThe main purpose of the cruise was to take measurements of the turbulence in the boundary layer close to the sea bed in areas of simple topography using electromagnetic flowmeters. In particular the intermittency in the turbulent momentum fluxes, the Reynold stresses, were to be examined at two levels in order to obtain data for a comparison with recently published laboratory work and for studies on sediment transport. Velocity profiles were also planned using an array for four rotor current meters and the bed shear stresses, calculated from the logarithmic profile using results averaged over one minute, would be compared with the Reynolds stress values. Additionally the turbulence data would be analysed for turbulent intensities, spectra, co-spectra and presented in the formats used by many other workers. An underwater television would be used for examining the water flow in the vicinity of the sensors, and to monitor changes in the form of the bed and sediment movement.
Experiments to measure the noise present near the sea bed in the frequency range of several kiloHertz to 400 kiloHertz were also to be carried out, as time permitted, to examine the contribution to the spectrum of the noise generated by the sediment when in motion.
Based on previous work seven positions had been chosen within Start Bay, a known area of fine/medium uniform sand with low shell content. It was anticipated that the areas would be rippled and that some of them would have small dunes present. The sands were expected to be mobile under extreme conditions.
Chief scientistKeith Dyer (Institute of Oceanographic Sciences Taunton)
Cruise reportRV Sarsia 15/75 cruise report sarsia15_75.pdf — access key 'C' (0.78 MB) 
Ocean/sea areas 
GeneralIrish Sea and St. George's Channel
Physical oceanography 
Current metersQuantity: 4
Other physical oceanographic measurementsQuantity: 2
Description: Electromagnetic current meters for turbulence measurements
Geology and geophysics 
Bottom photographyQuantity: 3
Description: TV-film of sea bed