1st – 6th March: Gulf of Cadiz

Measuring the Mediterranean outflow in the Gulf of Cadiz using current meters, a free fall probe, and an em sphere which is reluctant to come to the surface…

The EM Sphere

Sunday (1 March): Morning 0500Z launched [EM Flow Meter] sphere and then tripod. Continued with TSD’s, then in afternoon tried to release the sphere acoustically but no sign at the surface. By 1900 decided sphere still at bottom. Continued with TSD’s during night leaving sphere turned off at bottom to be grappled for later. Saw hoopoe and chiffchaff during day and a number of swallows during the night which was exceptionally mild (15.9°C) with some rain.

The Free-Fall Probe

Monday (2 March): Tripod recovered in the morning safely – seems to have worked. John Simpson’s [Free-fall] probe launched midday  but the ship being kept on a TSD station slewed into it, released the weights and left it drifting. On recovery it was found that considerable damage had been done.

The surface pinger on the sphere came on in late morning. This had happened previously and it had been decided that the sphere was still at the bottom held down by the recovery line or by the corrosive bolts which, covered with plastic caps to prevent bubbles getting near the EM head, had not all corroded [by the time that] the explosive bolt fired. The sphere has certainly been through the firing sequence. Any tilt of the sphere would bring on the pinger.

EM sphere successfully grappled

Preparations to grapple were made in the afternoon and the sphere tracked using hydrophones over the stern… when it was sighted at the surface. It was then successfully recovered.

Helped Steve Thorpe to read the sphere angle of tilt in the evening after watching the “St Valentines Day Massacre”! Long day – 3 x 4 hour watches. Rain this morning, cloudy but mild. Lightning in evening.

Tuesday (3 March): On watch in morning – TSD’s. Hot sunbathing afternoon with a water battle and launching of the Abyssal Pisa, a Dr Carruthers current device 1 simple sensors, which seemed to work. Sphere film [was] developed and [had] worked. Retired to bar after 6 to 8 pm watch in preparation for 0400Z watch tomorrow.

Wednesday (4 March): Coming off TSD watch at 0800 spent morning dozing in the sun. The Tripod was put down in the morning and the current sphere in the evening. After 1800-2000 watch saw “Guess Who’s Coming to Dinner” and then on watch 00Z to 04Z.

Recovering the John Simpson’s Free-fall probe

Thursday (5 March): Sunbathed in morning – there’s snow in Britain and a French submarine has been lost in the  MEDOC area 2 old news?. On watch in afternoon, TSD’s and John Simpson’s probe was put down – I saw it [first] at the surface near the port side 3 spotting gear.

On watch 2000 to 2400 streaming hydrophones to look for the sphere – beautiful starry night. Very glad to get to sleep for whole 7 hours.

Friday (6 March): Morning spent in [doing] TSD’s while Simpson probe successfully used, also preparations to drag for sphere in afternoon which was calm and very hot – almost unbelievably so. More sunbathing.

Started dragging for sphere in afternoon and throughout the night – method being to circle the sphere position at about 1 knot and then steam off hopefully dragging the cable over the sphere 4 grappling. I was put on radar measuring range and bearing of the current meter data buoy 5 radar watches at 10 minute intervals.

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 Science Notes: [(1) Current Meters ]  [(2) Bottom currents]   [(3) Free-fall Probe]