Cruise Report 13th April 1967

Cruise Report
F.R.S. "Explorer"
13th April - 18th May, 1967.

Narrative: "Explorer" sailed from Aberdeen at 02.00 hour on Thursday 13th April and proceeded to a position west of the Butt of Lewis. A line of plankton stations was worked on an echo-survey grid down the 100 fathom line to the west of the Hebrides and several deep-water stations were completed. The ship called into Campbeltown on Monday 17th April to land the Kelvin Highes representattive and after taking on water set out for the Porcupine Bank a few hours later. Trawling commenced at a position East of the Bank at 15.00 hours on Tuesday the 18th and gear testing of the bottom trawl continued, with only short interruptions due to the weather, until Sunday 23rd. The mid-water trawl was worked from Sunday until Wednesday 26th when, after one last bottom haul which came fast, the ship set sail for Greenock. Plankton stations were worked intermittently during the trawling operations and hauls were completed every 30 miles on the steam to Greenock. Very good time was made and "Explorer" docked, mid-trip, at 19.30 hours on Thursday 27th April.

After victualling and changing the scientific personnel, fuel was taken on board and "Explorer" sailed for Rockall Bank at 16.30 hours on Tuesday 2nd June. The line of plankton station out to the bank was twice interrupted by gale force winds and trawling did not start on the bank until Saturday 6th. On Sunday 7th a 24 hour station was worked about 100 miles S.E of Rockall and a trawl haul, with the camera, and multiple plankton sampling, were carried out every 4 hours. Large numbers of blue whiting larvae were being caught and it seemed clear that the ship was in an area of very high larval abundance. An echo plankton grid of the area was started on Monday 8th and continued in excellent weather until Sunday 14th. Eight transects were worked across the Bank and one from North to South. "Explorer" steamed close to Rockall on the evening of the 14th and the Decca and Loran readings were both checked. A course was then set for the "Anthon Dohrn" Bank between St. Kilda and Rockall and the ship worked an intensive grid of the area. It had been intended to trawl on the bank but it was discovered to be only a very sharp seamount with a minimum depth of about 288 fm. A line of plankton stations was worked North to Rosemary Bank where three transects were worked without any appreciable quantities of larvae being caught. Here again is was not found possible to trawl as the bottom topography was very eneven and no mid-water traces were seen. On Tuesday 16th a final line of stations was completed ENE to the Wyville Thomson Ridge and "Explorer" docked in Aberdeen at 21.00 hours on Thursday 18th June.

D.F.S Raitt
21st June, 1967