British Enterprise IV 84:BE:0B Leg6
Cruise summary report
|Ship name||British Enterprise IV|
|Cruise identifier||84:BE:0B Leg6|
|Cruise period||1984-10-13 — 1984-10-23|
|Port of departure||Scrabster, United Kingdom|
|Port of return||Leith, United Kingdom|
|Objectives||BGS charter - Routine sampling
Sailed from Scrabster 1330 on Saturday 10/13. Trials at sea to 1230 10/14 proved a design fault in the hydraulics and a prolonged period from 1510 10/14 Sunday to 1340 10/17 Wednesday was spent at anchor in Loch Eriboll. The ship sailed again on Wednesday, already half way through the leg, and twice drilled a low priority site (RD5/Sutherland) on the second attempt. On the next site off Cape Wrath the whole electrical control system was down and the ship returned to Loch Eriboll by 0100 Thursday 10/18. Thus, in the first week of the leg, only 37 hours had been spent at sea including passages.
Up to this time the weather had been reasonable, but thereafter conditions deteriorated drastically. In general the Minches stablished allowing judicious work at sea with continuous monitoring of the changing situation. Hebrides and Fair Isle were forecast to have almost continuous gales though only four were experienced. On Thursday 10/18 from 1100 to 1835 the ship shifted from Loch Eriboll to Stornaway Bay due to severe gales. At the anchorages the transformer and computer pots of the RD were again drained, re-made, had the electrics potted, were tested, and were resealed and filled with oil. The ship sailed at 0615 10/19 and attempted an RD site in Broad Bay despite a heavy northerly swell. The electrics retripped several times to earth after a few moments running. Pending further extensive fault finding on the RO, the ship was taken gravity coring and grab sampling on RO sites in the North Minch and RC sites in the Little Minch from 1630 10/19, Friday to 1830 10/20 Saturday. A lot of CR barrels were smashed but several rock out-crops proved. We anchored for the night of Saturday-Sunday off North Harris to make up the RO again, though operations were slowed by heavy rain, and sailed 0600 10/21 Sunday to Minch due to a forecast SE Gale. Some time was wasted since a return to Stornaway Bay was needed to refill the transformer pot. From 1630 to 2307 on 10/21 Sunday the RO performed well mechanically at 3 RO sites before anchoring in Enard Bay, Sutherland from a S-SE gale till 0730 10/22 Monday.
From 0815 - 1650 the RO again performed well mechanically at three further sites off Assynt and another RO site proved unsuitable for drilling with the gravity corer. At 1630 10/22 Monday the ship set off on passage for Leith but another RO site off Kyle of Tongue 20 nm west of the Pentland Firth was drilled from 2000 to 2300 10/22 Monday in marginal weather. Again the RO
performed well mechanically.
At 0001 10/23 Tuesday the ship proceeded towards Leith passing the Pentland Firth in a waterly gale Force 8 at Slack Water (Springs) from 0450 to 0600 10/23. Thus the RO (5 m) took almost continous major trouble shooting for the first 11 days of the leg and only achieved reliable mechanical operations at 7 sites over a period of 20 hours operations (1500 - 2000 Sunday, 0800 - 2300 Monday) including three hours on passage. None of these 7 sites yielded rock cores due to geological problems.
|Chief scientist||R T R Wingfield (British Geological Survey, Keyworth)|
|Cruise report||(7.36 MB)|
|General||North East Atlantic Ocean (limit 40W)|
|Specific||Continental Shelf and Slope off NE Scotland|