RRS Charles Darwin CD6

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Charles Darwin (74AB)
Cruise identifierCD6
Cruise period1985-08-09 — 1985-08-27
Port of departureFalmouth, United Kingdom
Port of returnFunchal, Portugal
Objectives1. To deploy and test 3 digital ocean bottom seismometers (DOBS).
2. To use the DOBS and 4 airguns for refraction lines to the SW of the UK; as far as possible (1) and (2) to be simultaneous.
3. In the absence of the 13.5 mm Rochester cable, to check the suitability of the CTD cable, and its winch reeving for limited depth, limited tension work.
4. Using the above cable and winch to deploy and test TOBI (a Towed Ocean Bottom Instrument), working towards an operational instrument for Darwin Cruise 9/85.
5. To deploy in GME and recover, then deploy again 2 off PUPPI (Pop-Up Pore Pressure Instruments) for recovery on Darwin Cruise 9/85 for an in-situ experiment to measure sediment porosity, for which the deep ocean tide signal provides the cyclical excitation pressure.
6. To test acoustic releases, including those for objectives 5 and 8.
7. To recover from GME a deep ocean tide gauge.
8. To deploy an inverted echo sounder for a few days and to recover.
9. To deploy and tow at a range of speeds a revised sea surface temperature/pressure fish, checking sensors and towing position and stability.
10. To test the Pore Water Sampler (PWS) using the torque balanced coring warp, with camera and sensors fitted but no water sampling tubes.
11. To do range tests on a miniature radar transponder (belonging to SPRI) mounted on a pitch-roll buoy float.
12. Calibration and intercomparison of the electromagnetic and doppler logs fitted to the ship were not possible because the Level A interface of the doppler log was not working.
Chief scientistBrian S McCartney (Institute of Oceanographic Sciences Wormley Laboratory)
Cruise reportRRS Charles Darwin CD6 cruise report cd6.pdf (0.60 MB) 
Ocean/sea areas 
GeneralNorth East Atlantic Ocean (limit 40W)
SpecificGreat Meteor East
Track chartsRRS Charles Darwin CD6 cruise track — trk3307.html
Physical oceanography 
Surface measurements underway (T,S)Description: trials of SSTP recorder T only
Sea level (inc. bot. press., inverted echosounder)Description: inverted echo-sounder
Sea level (inc. bot. press., inverted echosounder)Quantity: number of recoveries = 1
Description: Deep sea pressure recorder with temperature sensor
Geology and geophysics 
Core - soft bottomQuantity: number of cores = 1
Bottom photographyQuantity: number of deployments = 4
Long/short range side scan sonarQuantity: number of deployments = 3
Description: towed ocean bottom instrument(TOBI),test deployments only
Seismic refractionQuantity: number of deployments = 1
Description: digital ocean bottom seismograph(DOBS),noise level test
Other geological/geophysical measurementsQuantity: number of deployments = 2
Description: pore water pressures in sediments,2 long term deployments,(4month)