Cruise inventory

RV Farnella 2/81

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Farnella (74AE)
Cruise identifier2/81
Cruise period1981-10-16 — 1981-11-05
StatusCompleted
Port of departureSt John, Canada
Port of returnPonta Delgada, Portugal
PurposeResearch
ObjectivesGLORIA. Geophysical studies of the continental margin on the eastern edge of the Grand Banks.

Aim:
The main objectives were to study the structural and sedimentary processes which have shaped the continental margin to the east of the Grand Banks between 41° and 52° N, and to compare the geological history of this margin with that of its conjugate on the eastern side of the Atlantic.

Narrative:
Sailed to start of survey plan. GLORIA launched in high winds and poor visibility and 3.5kHz, PES and airgun deployed. The 3.5 kHz interfered with GLORIA and was abandoned. 19th October, gear reocover for engine repairs. 22nd October, the PDP11/CAMAC digitiser and SE 8000 tape recorder used to take digital GLROIA records for the first time. 30th October, the Grand Banks survey was complete including a box survey of the Newfoundland Seamounts. Course set towards Mid-Atlantic IPOD sites with GLORIA, PES and magnetometer streamed and SRP and 3.5 kHz recovered. Following day the magnetometer and GLORIA recovered due to worsening weather. GLORIA launched for the IPOD site survey on 2nd November and completed on 3rd. All gear including PES recovered and set sail for Ponta Delgada, Portugal.

5 sonobuoy stations: 6, 7 and 8 (1000m3 airgun), 10 and 11 (300m3 airgun).

Results:

GLORIA - 2-second pulse every 40 seconds used. Trouble was experienced with interference from the SRP but SRP not normally run. Problem of apparent beam widening, 47 tapes (3 digital), 8 hours each. 4600 nautical miles in total during cruise of seismic reflection data logged by the 3.5 kHz high resolution SRP. Compressors gave little trouble and all faults recorded were electrical. Each airgun was fun for 5 days. Barringer magnetometer performed well. The gravimeter produced a noisy but acceptable record, average errors of 3.66m gal. 5 sonobuoy stations successfully occupied during the cruise. 1 further buoys failed to transmit useful data.
Chief scientistJack A Revie (Institute of Oceanographic Sciences Wormley Laboratory)
Cruise reportRV Farnella 2/81 cruise report farnella1and2_81.pdf — access key 'C' (0.64 MB) 
Ocean/sea areas 
GeneralNorth Atlantic Ocean
SpecificN.W. Atlantic
Track chartsRV Farnella 2/81 cruise track — trk2895a.html RV Farnella 2/81 cruise track — trk2895b.html
Measurements 
Geology and geophysics 
Multi-beam echosoundingQuantity: track kilometres = 5600
Description: in total during 1/81 and 2/81
Long/short range side scan sonarQuantity: track kilometres = 5790
Description: GLORIA, 47 tapes (3 digital) of 8hours each, ~3600 miles
Multichannel seismic reflectionQuantity: track kilometres = 7400
Description: 4600 miles in total during 1/81 and 2/81, 2 channel array SPR used
Gravity measurementsQuantity: track kilometres = 15560
Description: in total during 1/81 and 2/81, average errors of 3.66 m gal
Magnetic measurementsQuantity: track kilometres = 10370
Description: in total during 1/81 and 2/81, Barringer magnetometer
Other geological/geophysical measurementsQuantity: number of deployments = 5
Description: sonobuoys, 3 with 1000m3 and 2 with 300m3 airgun