Chapter 5: My Voyage in Discovery II (continued)

There was little opportunity to make more than surface observations in meteorology. We had a theodolite fitted with gimbals but were unable to render it operational. Number one and I made some pilot balloon observations using two sextants. I suppose this was the only time such a method had been attempted. We did not achieve much success with our innovation.

Pilot balloon theodolite on Discovery II. Note the counterweight suspended from the gimbals on which the theodolite is mounted. This device was supposed to maintain the theodolite level when the ship pitched and rolled.

Comprehensive surface meteorological observations were made as part of the normal ship's routine.

I was recruited to assist in operating the echo-sounders. I did a four hour watch on the echo-sounders twice a day. There were two echo-sounders. One measured depths from 5 to 15 fathoms (9 to 27 metres). The other, a large Admiralty instrument, was for oceanic depths to 5,000 metres. A large compressed-air driven hammer was mounted on the keel and controlled from the bridge deck. The hammer could be set to beat the keel at fixed intervals (say 2.5 second) and the time taken to get the return signal determined the depth. The device was somewhat primitive with response times manually recorded. The shallow water echo-sounder had a recording device. But with both echo-sounders there was a considerable amount of labour in working up the results. It was pretty tedious.

Each night between 8pm and midnight local time, the darkest hours of the 24, the ship would heave to and Number one would take over the bridge. A buoy would be thrown overboard and a searchlight trained on it. It was Number one's job to direct the head of the ship and use the engine so that Discovery II remained stationary. If there was some wind it was easy to hold the ship's position by turning into wind and adjusting engine speed. But if there was no wind you had a problem. Number one gave directions to the engine room by phone because the use of the engine room telegraph was too difficult. When Discovery II was holding position soundings would commence.

Bureau of Meteorology