Blog 115 == Communications (and "Sparks") == GMDSS == Chip Logs == Speed Logs

Communications and Satellites - then and now

The humble post card that cost ½ an ‘Anna’, delivered within two days within a certain perimeter by a surprisingly efficient Postal Service, has now become an e-mail delivered in seconds to any destination in the world by the wonder that is the Internet.

The telephone-at-home could be afforded by only the very rich which left the average citizen the ‘telegram’ as the only medium to convey an urgent message, where you paid a higher rate if classed as ‘urgent’, once again through the auspices of the Post Office, has now become a cell phone in every hand, from which you could call or send a message to another person for an instant response.

Long distance calls were known as 'trunk calls' and could take as many as 12 hours to get connected. Very urgent ones were termed 'lightning calls' and took about 2 hours to connect.

The sailor who had signed on to a ship had to resign himself to communicating through infrequent letters. Telephone calls were expensive and needed the assistance of the Radio Officer (Sparks) for a connection to home. From mid sea, using the ship’s Radio Station, he would connect us, using the most approachable and clear Shore Station, who would connect the ship on to a land line. Very expensive and, almost always, never used.

As many countries spent more and more of their annual budget on upgrading their communication facilities, it became a little less expensive to make a call through the ship’s VHF connecting to a Shore Station. But still out of reach of a Third Engineer’s or Fourth Engineer’s pocket.

Next, in progression, came personal visits to Post Offices in ports to make International calls to home. Progressively cheaper. Cost about $2.50 per minute.

As communication technology brought in new innovations, public call boxes became common and, with the use of ‘phone cards of each nation to activate the public phones, more number of calls could be made.

Even as far back as the 1980s, the Japanese were very innovative. Each Japanese registered ship had a ‘Green Phone’ that used to get activated when in the proximity of a communication tower. A Japanese communications company, Docomo, set up such sophisticated communication towers even in the remotest of the Japanese islands, with hardly any habitation.

Thus, when about 500 miles from our destination port in the mainland, our ‘Green Phone’ would get activated and we would have clear conversations with family members. Cost about $1 per minute and less as the years went by. But this was available only on Japanese owned ships.

On board, starting from the mid 1980s, the IMO sponsored ‘Inmarsat’ phone came into existence, at the cost of $7 per minute. By the time I left sea in 2008, the cost had come down to around $3. Hardly used for personal calls. Calls to and from the Office were not uncommon.

Entities such as the International Labour Organisation and the International Transport Federation have been lobbying ship owners for decades to provide free internet service to their seafarers. Many of the larger companies started providing such services to their floating staff from around 2010, dishing out a restricted number of Megabytes per month to each of them. So families were just seconds away, figuratively.

From ‘Sparks’ to GMDSS

On the official side, the Radio Officer - affectionately called Sparks (and ‘Marconi’ Saab by the Indian crew) - and his Radio Station transmitting in Morse Code were the only link to the outside world, when on international voyages.

Some were grizzled veterans with a sense of humour, some cantankerous enough to rail against the world - what their complaint was, I never got to know - but the majority were simple, jolly people, near experts in their field. They protected their turf fiercely to the extent that, when he was on duty, were you to go into the Radio Room for a few minutes, you were made to feel unwelcome, even though he would be sitting and reading a magazine.

The Morse Code was his world, receiving and transmitting in short bursts, messages that were truncated to reduce the number of words - as any message was charged on the basis of the number of words - sometimes truncated to make the message almost incomprehensible.

The late 1970s saw the ship’s Radio Station with Morse Keypad becoming a ship’s Radio Station with a Telex Machine, with the Morse Keypad retained as a ‘standby’.

The first few Telex Machines were ones with teleprinters, very quickly replaced with long paper rolls.

As communications’ satellites became more prolific, shore radio stations started shutting down. On the ship, the Morse Keypad became redundant. The Morse Code was officially laid to rest in the year 2000.

The days of the Radio Officer were numbered with the introduction of GMDSS - Global Maritime Distress Safety System - as the package equipment primarily contained software and hardware for sending out distress signals for emergencies. But they also contained simple to use equipment for sending out and receiving standard messages.

‘Sailor’ 2000 GMDSS

Courtesy Wikipedia

Quoting from “Marine Insight”

The different elements of GMDSS:

1. INMARSAT: It is a Satellite operated system that includes ship earth station terminals – Inmarsat B, C and F77. It provides telex, telephone and data transfer services between ship-to-ship, ship to shore, and shore to ship along with a priority telex and telephone service connected to shore rescue centres.

2. NAVTEX: NAVTEX is an internationally adopted automated system which is used to distribute MSI-maritime safety information, and includes weather forecasts and warnings, navigational warnings, search and rescue notices and other similar safety information.

3. Emergency Position Indicating Radio Beacon (EPIRB): EPIRB is equipment to help determine the position of survivors during a SAR operation. It is a secondary means of distress alerting. Read about EPIRB here.

4. Search and Rescue Locating Equipment: Primarily the Search and Rescue Radar Transponder. This is used to home Search and Rescue units to the position of distress which transmits upon interrogation. Read about Search and Rescue equipment here.

5. Digital Selective Calling (DSC): This is a calling service between ship to ship, ship to shore or vice versa for safety and distress information mainly on high or medium frequency and VHF maritime radio.

End Quote

It was made mandatory for all Navigating Officers to get training to handle the GMDSS equipment.Personally, I learnt to handle the GMDSS from several Captains, more as a personal interest.

The Radio Officer had, by the mid 1980s, taken over all the duties of the Purser, who had been quietly whisked away from all ships. After the induction of GMDSS, some companies continued to retain the Radio Officer for a few more years, but one could plainly see the writing on the wall.

A group of good people were, thus, forced out of the Maritime Industry.

Today’s GMDSS Console

“Global Maritime Distress and Safety System (GMDSS) uses Earth and satellite technologies, as well as ship radio systems. The components of this system on the ship are VHF, MF/HF with DSC, Navtex, radiotelex, SART, EPIRB, Inmarsat-C.”

The Ship’s Speed Log

From time immemorial, man has tried to measure what speed his ship was doing.

“In the ancient times, the only way to measure ship speed was to throw a wood log into the water and observe how fast it moves away from the ship. This approximate method of ship speed measurement was called ‘Heaving the Log’ and was used until 1500-1600s when the ‘Chip Log’ method was invented (both methods probably invented by Dutch sailors.)

The ‘Chip Log’ apparatus consisted of a small weighted wood panel that was attached to the reel of rope, and a time measuring device: a half-minute sand glass (as shown in image below to the right.) The Chip Log Rope had knots tied at equal distances along the reel. Sailors would throw the wood panel into the sea, behind the ship, and the rope would start unwinding from the reel. The faster the ship was moving forward the faster the rope would unwind. By counting the number of knots that went overboard in a given time interval, measured by the sand glass, they could tell the ship’s speed. In fact that is the origin of the nautical speed unit: the knot.

The ‘patent log’ came into use in the 10th century. Basically, a vaned rotor is towed at the end of a line astern and the revolutions are counted. Then came the ‘towed log’.

Courtesy Smithsonian

Courtesy ‘Cult of the Sea’

My first experience of ‘speed logs’ was with the ‘Pitot Tube’ type. Lowering it after “Full Away” and raising it at “Standby” before arrival port was the job of the Duty Engineer. The instructions for doing so were supposed to come from the Bridge, but invariably would be forgotten.

This Pitot Tube, when lowered, would protrude below the keel by less than a metre and hence had to be retracted before coming to shallow waters, to avoid damage.

CourtesyWikipedia

Courtesy Cult of the Sea

Electro Magnetic Speed Log

“An Electromagnetic Log, sometimes called an "EM Log", measures the speed of a vessel through water. It operates on the principle that:

1 when a conductor (such as water) passes through an electromagnetic field, a voltage is created and

2 the amount of voltage created increases as the speed of the conductor increases.”

Courtesy Slide Player

Courtesy Marine Gyaan

Courtesy Marcom Systems

Courtesy Radio Holland

Doppler Log

The most commonly used instrument to track the ship’s speed today is the Doppler Log. “Doppler log is an instrument, used in ships, to measure ship's relative speed with water (in which it is travelling) by the use of Doppler effects on transmitted/reflected sound waves. Display of a dual axis Doppler speed log which shows the vessels movement in the Fore and Aft as well as the Athwartship direction.”

Courtesy Cult of Sea

Working Principle

The principle of Doppler Speed Log & the Janus configuration of the transducer

Courtesy Globalspec

Satellite speed log

Satellite speed log is a bit different from the earlier mentioned speed logs. The satellite speed log provides us the speed over ground.

The satellite speed log is introduced because of the speed accuracy it provides. No matter which type of weather it is outside, the satellite speed log provides us the accurate speed upto an error of 0.02 kts or 0.2%.

Satellite speed log works on the GPS signals, which enhances the accuracy of the measured speed of the vessel.

Because of the accuracy of the speed over ground provided by the satellite log, this is used for berthing and unberthing operations.

The satellite speed log provides us the fwd and aft speed as well as the athwartship speed of the vessel.

Courtesy Furuno

===== Continued in Blog 116 =====