Cruise inventory

RRS John Murray JM8/69 Leg 2

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS John Murray (74MJ)
Cruise identifierJM8/69 Leg 2
Cruise period1969-10-11 — 1969-10-21
StatusCompleted
Port of departureBarry, United Kingdom
Port of returnBarry, United Kingdom
PurposeResearch
Objectives1) To measure the noise levels of towed hydrophone arrays under different conditions including ship speed.

2) To record the noise spectrum of the ship under different engine conditions,

3) To make extensive tests of recent design modifications to the air-gun and to test its reliabilty.

4) To obtain Grab samples from five areas of small sand waves to the south of the Isle of Wight.
Chief scientistBrian S McCartney (National Institute of Oceanography)
Cruise reportRRS John Murray JM8/69 Leg 2 cruise report john_murray8_69_leg2.pdf — access key 'C' (0.31 MB) 
Ocean/sea areas 
GeneralEnglish Channel
SpecificIsle of Wight and Channel Islands
Measurements 
Biology and fisheries 
Gear researchDescription: 9 N.I.O hydrophones ranging in size were towed and noise spectra obtained at 3 ship speeds
Gear researchDescription: Solenoid triggered air guns tested: solenoids; top liners; leakage, lower and upper flange
Geology and geophysics 
GrabQuantity: number of hauls = 33
Description: sediment samples
Single channel seismic reflectionDescription: 9 N.I.O hydrophones ranging in size were towed and noise spectra obtained at 3 ship speeds
Magnetic measurementsDescription: 9 N.I.O hydrophones ranging in size were towed and noise spectra obtained at 3 ship speeds
Other geological/geophysical measurementsDescription: 'Ewing' type air gun high versus low pressure readings obtained