Role of the Weather Ships

The Weather Ships were based in Greenock on the Clyde at the James Watt Dock. They sailed out to stations in the Atlantic as indicated on the map below

The stations were manned as follows:-

Great Britain - A,I,J,K France - A,J,K Holland - A,I,J,K,M

USA - B,C,D,E Canada - B Norway - M

Role of the Weather ships page 1

By 1975 the stations were reduced to those in the map below

Time on station was 28 days with 3 days either side to sail to/from station/base.Once at station at the correct co-ords the engine was cut and the ship allowed to drift from the centre point (known as "Middle for Diddle") as far as 100 miles when the engine was restarted and the ship positioned back to statio, also during heavy weather the engine was used to maintain steerage and keep station.

The crew consisted of 57 men,14 Deck crew, 15 Engine room, 10 Galley, 11 Radio/Radar personnel and 7 Met Office staff. (on ex Castle Class ships)

Weather conditions were recorded day and night and transmitted to Bracknell, Each watch launched a balloon with an attached Radio-Sonde to collect data in the upper atmosphere.

The ships also had the role of Search & Rescue should any Ship or Aircraft be in trouble in the area and to act as a navigational beacon for transatlantic aircraft.

The following text and pictures courtesy of Dave Offiler

Taking a bucket sample and using a Salinometer

The experiment investigated how the sea surface salinity changes during rain, which means taking samples of the seawater by the ages-old method of chucking a canvas bucket overboard (and not letting go of the other end of the rope!).

Those observant among you may spot that it's not actually raining here. But it's coming, so were getting the 'before' measurement. A 'salinometer' is a fancy term for a gizmo that measures the saltiness of water. Seawater is normally around 35 part salt per 1000 parts of water. We had to lug this box of tricks (which came in a bigger packing crate) by hand on the train from Reading to Greenock and back. I expect these things are smaller than a mobile phone these days. The theory goes that rain dilutes the surface water, so the salinity should go down the more it rains. In practice, when it rains at sea, its also windy. This stirs up the surface water, and the salinity doesn't change at all.

How a weather balloon works.

Part one - blow it up with hydrogen. Beware of sparks

Part two - attach a mesh radar reflector and a 'can'. The silver thing the chap on the right is holding is a radiosonde (or rawinsonde to any US readers). This measures pressure, temperature and humidity every few seconds as the balloon rises though the atmosphere to around 30km (20mi or 100,00ft in round numbers), tracked by the radar to obtain its height and the wind speed and direction

Part three - bring the balloon out of the shelter and let it go. But keep hold of the 'can' to stop it bashing against something before it even gets started.The chap on the left is about to press a button to signal to the radar operator that the launch is successful and to start tracking.

Part four - let go!

Tracking the balloon

While the radar operator next door tracks the position of the balloon, here in the met. office, the radio signals are decoded from the pen chart recorder (by hand, in real-time) into calibrated pressure, temperature and humidity values from the sonde sensors.

When the balloon gets so high that it bursts, the sounding is complete, and the sonde measurements, together with the radar-tracked winds, are coded up and sent by the radio operator back to Headquarters in Bracknell in Morse code. 1973 was way before the digital age and satellite communications; ship-to-shore voice reception was poor to bad and prone to errors, but Morse was very reliable, and experienced operators could transmit the data in a few minutes. Today, of course, observations can be squirted back via high-speed digital satellite links in milliseconds.

Radio/Radar Technician (Euan McDonald) tracking balloon (Bearing, elevation, range every minute.)

Plankton Recorder

A Nansen bottle is a device for obtaining samples of seawater at a specific depth. It was designed in 1910 by the early 20th-century explorer and oceanographer Fridtjof Nansen and further developed by Shale Niskin.

The bottle, more precisely a metal or plastic cylinder, is lowered on a cable into the ocean, and when it has reached the required depth, a brass weight called a "messenger" is dropped down the cable. When the weight reaches the bottle, the impact tips the bottle upside down and trips a spring-loaded valve at the end, trapping the water sample inside. The bottle and sample are then retrieved by hauling in the cable.

A second messenger can be arranged to be released by the inverting mechanism, and slide down the cable until it reaches another Nansen bottle. By fixing a sequence of bottles and messengers at intervals along the cable, a series of samples at increasing depth can be taken.

The sea temperature at the water sampling depth is recorded by means of a reversing thermometer fixed to the Nansen bottle. This is a mercury thermometer with a constriction in its capillary tube which, when the thermometer is inverted, causes the thread to break and trap the mercury, fixing the temperature reading. Since water pressure at depth will compress the thermometer walls and affect the indicated temperature, the thermometer is protected by a rigid enclosure. A non-protected thermometer is paired with the protected one, and comparison of the two temperature readings allows both temperature and pressure at the sampling point to be determined.

Bathythermograph recovery

A bathythermoraph is a small torpedo shaped device that holds a temperature sensor and a transducer to detect changes in water temp against depth. It is lowered into the sea from a ship and records pressure and temp changes as it is dropped through the water,because pressure is a function of depth temperature measurements can be correlated with the depth at which they are recorded.

A series of photos showing Derek Ogle carrying out a Bathy descent

A Radio Sonde

Balloon ready to launch from Monitor

Roger Marshall at the OWS position at Portishead Radio. Weather reports were linked to Bracknell from the 4 Weather Ships by Radiotelex, who would be `Polled` at scheduled times to obtain their reports

http://www.gka.btinternet.co.uk

Weather Reporter Boat Drills

A marine biologist being transferred between ships.

Monitor taking part in an Air-Sea rescue exercise, with Tommy Sandham in the foreground

Photos of an air sea rescue exercise from Weather Surveyor.

David Lord says "Chris Jackson and Myself were volunteer divers on such occasions and had to don dry suits and leap into the sea and rescue a dummy. We got a tot for our efforts"

Lifeboat Drills