kc
11-02-2008, 21:47
The following is an article from Ships and Ship Models, 1933.
Cable Ships and How The Do Their Work by John W Doddridge.
The cable-laying and repairing ship differs in many ways from all other sea-going craft, and in order to get full details concerning the construction and working of a vessel of this type, I recently paid a visit to the c.s. Marie Louise Mackay, of the Commercial Cable Company. I was accorded the greatest attention and courtesy hy Captain Dillon and his staff. I am indebted to Captain Dillon for some very excellent photographs, which are reproduced herewith.
The c.s. Marie Louise Mackay is a vessel of 1,378 gross tons and was built in 1922. She is 246' long, and has a breadth of 34' 2". She is stationed at Plymouth, together with the John W Mackay and the Mackay-Bennett. The John W Mackay is one of the largest cable vessels in the world and was built in 1921 and has a gross tonnage of 4,049. She was formerly stationed at Halifax, N.S., but came to Plymouth about two or three years ago. The Mackay-Bennett is a cable-storage hulk.
The chief distinguishing features of a cable ship are the very tall masts and the tapered bow with its large revolving drums, known as sheaves, over which the Cable is brought into the vessel. The hull of the ship is mainly taken up by three, and, in larger ships, four or five, large, circular tanks in which the cable is stored. These average about 27' in diameter and can contain about thirty or more miles of cable. When a cable is being paved out, it is liable to thrash about in the tank and cause damage. To prevent this, it is passed through an iron ring which works up and down a central hub and thus confines the cable's antics to very small area.
http://www.battleships-cruisers.co.uk/images/cs1.jpg
On the forward deck is arranged a system of leads over which file cable is passed from the hows into the tanks. On the Marie Lousie Mackay, there are five leads in pairs, the third of which is attached to an instrument known as the dynamometer, which registers the strain on the cable rope. Below decks, close to the first storage tank, are situated two very powerful winding engines which coil in or pay out the cable. On the John W Mackay the cable is taken the length of the ship and paid out through the stern, but on the Marie Louise it is paid out over the bows, as this vessel has no stern lead.
The electricians and wireless operators are very important people on a cable ship, as the former have to make very delicate and accurate tests of the cable's strength and transmitting power, while the latter have to keep constant contact with ship and shore. Whenever a break or leakage occurs in a cable, approximate bearings are obtained by the company's shore electricians and are telegraphed to the repair ship. From the charts, the path of the cable is ascertained and an instrument known as a galvanometer is used to ascertain the distance of the break from the shore. The frequent disturbances of the seabed, however, will often cause the cable to move some distance from its charted position, and it is necessary to fish for the cable, sometimes over quite a large area.
To hook the cable, specially designed grapnels are used, according to the type of sea floor over which the cable lies. In the Atlantic, Pacific, etc., the seabed is mostly covered with a soft ooze and a sharp-pointed grapnel has to be used; whereas, on a rocky bed such as might be found near the shore, the " flatfish " type is used. The grapnel is attached to a long rope and cast overboard and in deep water takes about an hour and a half to reach the bottom. When the grapnel has reached the bottonn, the cable ship steams verv slowly at right angles to the cable. The grapnel rope is passed under the dynamometer leads and a sudden stress on the rope is immediately registered by the indicator. A strain of 2,000 lbs. or over is necessary before the captain can be sure that a cable has been hooked.
http://www.battleships-cruisers.co.uk/images/cd2.jpg
The winding engines now start to reel in the grapnel rope and eventually the cable is brought to the surface of the water. Two men are lowered in bosun's chairs from the davits right in the hbows and make fast the cable to the ship, while the grapnel is remoVed. This job has to be done quickly, lest the weight of the cable and the sharpness of the grapnel hook should snap it. On the foredeck are carried a number of large buoys capable of sustaining a weight of two or more tons, and one of these is now lowered into the water and brought to the bows. The cable is cut and one end is made fast to the buoy and the latter is anchored. The other end is brought up over the bow sheaves and is made fast. Various types of anchors are used for the buoys. Some companies favour the " mushroom " type but once this anchor has worked loose, it cannot dig itself in again, whereas a more piked anchor can.
The cable on deck is connected hy an electric wire to a very delicate testing piece below decks. This wonderful instrument indicates the slightest fault in the Cable and testing continues as the cable is reeled in until the faulty section is reached. This is removed and a new section spliced on. The other end of the cable is released from the buoy and is spliced to the repaired length and the whole is once more relaid to do duty until another submarine earthquake or eruption breaks it again.
The cable buoys are fitted with bright lights at night, and these have to be changed when burnt out. In ordinary weather it is no easy task, but in stormy times it is very dangerous. One of the accompanying photographs shows the lights being changed on a cable buoy in the Gulf 5treamm. It is possible, Captain Dillon says, to commence operations in practically a dead calm and yet within the space of two hours or so the Stream can be seen in action, so to speak, travelling at the rate of three or four knots. In the photograph the water can he clearly seen racing past the buoy. Cable work is indeed a matter of extremes, and another photograph shows one of the cable buoys frozen to the shrouds. On certain occasions the vessel has become so frozen up that it has been necessary to proceed to the Gulf Stream to thaW out, and then return to the scene of operations, which is probably somewhere off the coast of Newfoundland.
http://www.battleships-cruisers.co.uk/images/cs3.jpg http://www.battleships-cruisers.co.uk/images/cs4.jpg
In northern waters many difficulties lie in the path of the cable repair ship, of which two are floating pack ice and icebergs. The accompanying photograph shows a small iceberg which had come to rest directly over a cahble which runs ashore through this cove. A small tug, to be seen in tile background, was employed to tow the iceberg off, but it was found to hbe immovable. Eventually, the captain of the repair ship decided to blow it up. A boat was lowered and seamen fixed a number of dynamite charges in the berg and gradually it broke up but it took twenty-seven charges to do it!
It is rather interesting to note that in shallow water the damage to the cable is more frequent than in deep water. This is due to the rocky under-surface of the coasts and to fishing vessels' trawls. In deep water the cable very often lies two or three miles below the surface and only such things as a submarine earthquake or other natural disturbance of the sea bed are likely to cause damage, though in their time even deep-sea monsters have played havoc with these electric ropes.
The accommodation on a vessel like the Marie Louise Mackay is of the very best and she has a spacious dining room and lounge.
http://www.battleships-cruisers.co.uk/images/cs5.jpg
It may be of interest to note the composition of the cable itself. The currcnt passes through a solid Copper conductor around which are wound copper wires. These are in turn covered by a thin ribbon of nickel-iron alloy. This is one of the newest improvements in cable manufacture and is called permalloy. This is insulated by a covering of gutta-percha. Next there is a layer of jute yarn and around this are wound the heavy sheathing wires, of about 1/4" diameter. The whole is now covered with it binding of tarred cotton tape and again protected by two layers of tarred jute. In deep water the sheathing is much less than in shallow water.
These cable repair ships are continually active and are stationed all over the Nvorld. There is always some danger connected with the work, and very often, when going to change the lights on a buoy, the boat has been smashed while launching or else swamped by the heavy seas. However, the cables must be repaired, and so it eventually becomes just a matter of "all in the day's work"
Cable Ships and How The Do Their Work by John W Doddridge.
The cable-laying and repairing ship differs in many ways from all other sea-going craft, and in order to get full details concerning the construction and working of a vessel of this type, I recently paid a visit to the c.s. Marie Louise Mackay, of the Commercial Cable Company. I was accorded the greatest attention and courtesy hy Captain Dillon and his staff. I am indebted to Captain Dillon for some very excellent photographs, which are reproduced herewith.
The c.s. Marie Louise Mackay is a vessel of 1,378 gross tons and was built in 1922. She is 246' long, and has a breadth of 34' 2". She is stationed at Plymouth, together with the John W Mackay and the Mackay-Bennett. The John W Mackay is one of the largest cable vessels in the world and was built in 1921 and has a gross tonnage of 4,049. She was formerly stationed at Halifax, N.S., but came to Plymouth about two or three years ago. The Mackay-Bennett is a cable-storage hulk.
The chief distinguishing features of a cable ship are the very tall masts and the tapered bow with its large revolving drums, known as sheaves, over which the Cable is brought into the vessel. The hull of the ship is mainly taken up by three, and, in larger ships, four or five, large, circular tanks in which the cable is stored. These average about 27' in diameter and can contain about thirty or more miles of cable. When a cable is being paved out, it is liable to thrash about in the tank and cause damage. To prevent this, it is passed through an iron ring which works up and down a central hub and thus confines the cable's antics to very small area.
http://www.battleships-cruisers.co.uk/images/cs1.jpg
On the forward deck is arranged a system of leads over which file cable is passed from the hows into the tanks. On the Marie Lousie Mackay, there are five leads in pairs, the third of which is attached to an instrument known as the dynamometer, which registers the strain on the cable rope. Below decks, close to the first storage tank, are situated two very powerful winding engines which coil in or pay out the cable. On the John W Mackay the cable is taken the length of the ship and paid out through the stern, but on the Marie Louise it is paid out over the bows, as this vessel has no stern lead.
The electricians and wireless operators are very important people on a cable ship, as the former have to make very delicate and accurate tests of the cable's strength and transmitting power, while the latter have to keep constant contact with ship and shore. Whenever a break or leakage occurs in a cable, approximate bearings are obtained by the company's shore electricians and are telegraphed to the repair ship. From the charts, the path of the cable is ascertained and an instrument known as a galvanometer is used to ascertain the distance of the break from the shore. The frequent disturbances of the seabed, however, will often cause the cable to move some distance from its charted position, and it is necessary to fish for the cable, sometimes over quite a large area.
To hook the cable, specially designed grapnels are used, according to the type of sea floor over which the cable lies. In the Atlantic, Pacific, etc., the seabed is mostly covered with a soft ooze and a sharp-pointed grapnel has to be used; whereas, on a rocky bed such as might be found near the shore, the " flatfish " type is used. The grapnel is attached to a long rope and cast overboard and in deep water takes about an hour and a half to reach the bottom. When the grapnel has reached the bottonn, the cable ship steams verv slowly at right angles to the cable. The grapnel rope is passed under the dynamometer leads and a sudden stress on the rope is immediately registered by the indicator. A strain of 2,000 lbs. or over is necessary before the captain can be sure that a cable has been hooked.
http://www.battleships-cruisers.co.uk/images/cd2.jpg
The winding engines now start to reel in the grapnel rope and eventually the cable is brought to the surface of the water. Two men are lowered in bosun's chairs from the davits right in the hbows and make fast the cable to the ship, while the grapnel is remoVed. This job has to be done quickly, lest the weight of the cable and the sharpness of the grapnel hook should snap it. On the foredeck are carried a number of large buoys capable of sustaining a weight of two or more tons, and one of these is now lowered into the water and brought to the bows. The cable is cut and one end is made fast to the buoy and the latter is anchored. The other end is brought up over the bow sheaves and is made fast. Various types of anchors are used for the buoys. Some companies favour the " mushroom " type but once this anchor has worked loose, it cannot dig itself in again, whereas a more piked anchor can.
The cable on deck is connected hy an electric wire to a very delicate testing piece below decks. This wonderful instrument indicates the slightest fault in the Cable and testing continues as the cable is reeled in until the faulty section is reached. This is removed and a new section spliced on. The other end of the cable is released from the buoy and is spliced to the repaired length and the whole is once more relaid to do duty until another submarine earthquake or eruption breaks it again.
The cable buoys are fitted with bright lights at night, and these have to be changed when burnt out. In ordinary weather it is no easy task, but in stormy times it is very dangerous. One of the accompanying photographs shows the lights being changed on a cable buoy in the Gulf 5treamm. It is possible, Captain Dillon says, to commence operations in practically a dead calm and yet within the space of two hours or so the Stream can be seen in action, so to speak, travelling at the rate of three or four knots. In the photograph the water can he clearly seen racing past the buoy. Cable work is indeed a matter of extremes, and another photograph shows one of the cable buoys frozen to the shrouds. On certain occasions the vessel has become so frozen up that it has been necessary to proceed to the Gulf Stream to thaW out, and then return to the scene of operations, which is probably somewhere off the coast of Newfoundland.
http://www.battleships-cruisers.co.uk/images/cs3.jpg http://www.battleships-cruisers.co.uk/images/cs4.jpg
In northern waters many difficulties lie in the path of the cable repair ship, of which two are floating pack ice and icebergs. The accompanying photograph shows a small iceberg which had come to rest directly over a cahble which runs ashore through this cove. A small tug, to be seen in tile background, was employed to tow the iceberg off, but it was found to hbe immovable. Eventually, the captain of the repair ship decided to blow it up. A boat was lowered and seamen fixed a number of dynamite charges in the berg and gradually it broke up but it took twenty-seven charges to do it!
It is rather interesting to note that in shallow water the damage to the cable is more frequent than in deep water. This is due to the rocky under-surface of the coasts and to fishing vessels' trawls. In deep water the cable very often lies two or three miles below the surface and only such things as a submarine earthquake or other natural disturbance of the sea bed are likely to cause damage, though in their time even deep-sea monsters have played havoc with these electric ropes.
The accommodation on a vessel like the Marie Louise Mackay is of the very best and she has a spacious dining room and lounge.
http://www.battleships-cruisers.co.uk/images/cs5.jpg
It may be of interest to note the composition of the cable itself. The currcnt passes through a solid Copper conductor around which are wound copper wires. These are in turn covered by a thin ribbon of nickel-iron alloy. This is one of the newest improvements in cable manufacture and is called permalloy. This is insulated by a covering of gutta-percha. Next there is a layer of jute yarn and around this are wound the heavy sheathing wires, of about 1/4" diameter. The whole is now covered with it binding of tarred cotton tape and again protected by two layers of tarred jute. In deep water the sheathing is much less than in shallow water.
These cable repair ships are continually active and are stationed all over the Nvorld. There is always some danger connected with the work, and very often, when going to change the lights on a buoy, the boat has been smashed while launching or else swamped by the heavy seas. However, the cables must be repaired, and so it eventually becomes just a matter of "all in the day's work"