History of the Atlantic Cable & Undersea Communications
from the first submarine cable of 1850 to the worldwide fiber optic network
Memoirs of an STC Project Engineer - Part 3
by David Watson
|
History of the Atlantic Cable & Undersea Communications |
|
Memoirs of an STC Project Engineer - Part 3 |
|
1969 - March - GERMANY-SWEDEN - Land-based Operations I was asked to prepare for a land-based repeater operation due to take place in Malmo, in the south of Sweden. Steve Vincent, the STC operations manager, and I had been allocated this project, which entailed catching a ferryboat from Harwich to Esbjerg in Denmark, driving across country to Copenhagen and, by means of another ferry, on to Malmo. An experience I was really looking forward to. I spent a couple of weeks gathering together and checking out the test gear and jointing equipment that would be required for the operation and after arranging all the documentation for customs etc., proceeded to load it on to a Ford Transit van that I had borrowed from STC Basildon. After completing all the necessary work, one morning in mid-March of 1969 we set off for Harwich.
After an uneventful crossing to Esbjerg, we drove the van across Denmark, encountering snowdrifts and very cold weather. The Danes take the sort of snow that brings England to a halt in their stride and the traffic, with the help of the occasional snow plough, was fairly fast moving, so we reached Copenhagen just after lunch. The main car ferry that plies from the Danish capital across to Malmo was fully booked but we were told that a small tramp steamer that was sitting in the dock might have room. We had a word with a member of the crew and our luck was in, or at least I thought so until I saw the method that entailed getting the vehicle on board. Two planks of wood similar to those used on building sites were placed between the dock and the side of the ship, and after lining these up with the front wheels of the van one proceeded to drive across. Steve reckoned that I had the better head for heights and refused to take the wheel, so with feelings of trepidation and one hand on the door handle ready for a quick exit, I drove up the planks and on into the cargo bay, a distance of some fifty-odd feet. I'm not sure what would have happened if I had toppled off into the drink, as the water below was freezing cold. We required the assistance of an Icebreaker to get us out of the docks.
On arriving in Malmo, I booked into the Kronen Hotel, a very up-market place in a square some five minutes walk from the ferry. The next morning Steve and I walked to the offices of the Danish P&T some ten minutes away. It was a beautiful morning with blue skies, but very, very cold. Minus twenty, in fact. The coldest weather that I have ever experienced, before or since. During the day we drove out to the site where the cable was to be landed. The sea was still frozen from the winter but was just starting to thaw. Quite a sight.
The following day we drove the van to Helsingborg docks to observe the off-loading from a freighter of the two repeaters that were to be jointed on to cable tails. These tails would eventually be jointed onto the main system cable.
In the following days the time came to joint the repeaters to the tail cables. On the old analogue systems that we supplied in the era prior to the modern day fibre optics, the cable to repeater joint was made up of seven strands of 0.036" copper wire with a layer of polythene over the top, making an overall diameter of 0.310". A length of this was attached to the main cable by a taper joint made in the factory during the manufacturing process, and another length attached to the repeater. These two 0.310" tails had to be joined together. The jointing process involved stripping back the polythene on each end to expose the copper wires and, by means of a machine, brazing the copper ends together.
Once the brazed joint had been examined, it was placed into a mould and by means of an extruder, molten polythene was forced into the mould to cover the wires. The cooling process was carried out by using a pump passing water around the outside of the moulded area. This process was very critical to the well-being of the joint, as any fast cooling could cause voids in the polythene, thereby making the joint fail on system power up.
To keep the cooling temperatures correct when the same type of joint was made on board ship in warmer climes, ice would be put into the water supply tank to keep the temperatures up. Out in Sweden we had the reverse. With the outside temperature still down to minus twenty, we were pouring boiling water into the tank to stop the crash cooling that was taking place. Instead of the usual cooling down period of forty odd minutes the joint was setting in about fifteen. Frantic telephone calls were made to Frank Jarvis, the Chief Mechanical Engineer at North Woolwich, for advice, but none was forthcoming as no-one had tried jointing at these low temperatures before. We had no option but to carry on regardless, so the rest of the joints were made with our fingers crossed. To this day I have never heard from the Swedish purchasers stating that the joints had gone down, so perhaps we took too much notice of the cooling process specifications in those days. After making the 0.310” joints, we assisted in installing the land based repeaters into the jointing chambers, in this case just a large trench that had been dug previously during the warmer weather. A light smattering of snow was in the air as we lowered the repeaters into the trench.
Each repeater had to be wrapped in a water-resistant tape to help prolong any deterioration of the housings and to avoid undue water ingress. The wrapping was done by the Swedish jointers under my instructions, but obviously they had to be shown how, as they had never seen the operation before. After the repeaters had been installed, the main land cables were jointed to the attached tails.
This system was 5 MHz, and it never ceases to amaze me that as many as 480 telephone calls could be made in either direction simultaneously through this little piece of cable. During the mid 1980s this figure had increased with the advent of 45MHz systems to 5,600 circuits, and now the present day optical systems carry as many as 30,000 circuits plus. Where does it all end?
After completion of the operation, Steve had to go across to Germany so I was left to drive home by myself. Leaving Malmo at around 9.30 a.m. I took the car ferry over to Copenhagen. The weather by now was a lot warmer and most of the ice and snow that we had experienced on the way out had melted. An STC rule in those days was that two people should always be with the vehicle so that somebody could look after the expensive test gear that we were carrying in the event of a breakdown or whatever, but due to Steve's leaving for Germany I was lumbered with it all by myself. Luckily the Transit van behaved itself, and after an uneventful drive I arrived in Esbjerg to catch the evening ferry home.
1969 - April - GERMANY-SWEDEN -Load & Lay In the middle of April I went to supervise the jointing-in of the shore end repeaters on the Danish Cable Ship Peter Faber alongside 109 Berth, Southampton, and in the first couple of weeks of May assisted in the loading of the John W Mackay for the main lay.
After the John W. was finished loading we sailed for Sweden . As soon as we had left Southampton Water, on turning into the English Channel we ran straight into a force-eight gale. It was early evening just after dinner, and for the people who were not used to the ways of the sea it was very unfortunate. No time to get their sea legs.
By the time we reached the Kiel Canal, the passageway that separates the Atlantic from the Baltic sea, the winds had fallen away and the seas had become calmer. It's amusing to be on a ship going through a canal which is very narrow - it gives one the impression of floating along in the middle of a road with cars either side of you, and little men running up and down as they make them selves busy opening lock gates. The weather changed completely once we were into the Baltic; I've never seen such calm sea - so flat in fact that one could read the ship's name in the reflection on the water. In the early days prior to the installation of linear cable engines, five large wheels were used to pass the cable into the sea. These were called “V-sheave gears” and were used to hold the cable back from falling into the sea under its own weight, and to control the laying speed. The repeaters obviously could not pass into this gearing and had to bypass the wheels. This was achieved by the use of a bypass rope that was attached to the repeater. The rope was guided into the V-sheave in place of the cable, and the repeater was man-handled by the crew to “bypass” the cable gear.
Also, to stop the repeater dropping to the ocean bed too fast, a parachute was deployed as the repeater hit the water surface. This theory was dispelled in later years. As normal, the lay of 121 n.m. of cable went off without a hitch, apart from, as we found later, laying part of the system through a Second World War minefield just off the coast of Germany. A good way of protecting cable from fishermen!
At the end of the lay the spare cable had to be off-loaded into the depot in Korsor. On completing this we left the ship and travelled back to Copenhagen by train, flying out a couple of days later for home. Expedition images and text copyright © 2006 David Watson Read all of David Watson's memoirs:
|
|
Last revised: 7 June, 2011 |
|
-02.jpg)
