Blog 116 == VDRs == BNWAS == Echo Sounders == Barometers & Barographs

Voyage Data Recorder

Akin to the ‘Black Box’ of an aircraft, Voyage Data Recorders have become mandatory for ships from 2002.

“Passenger ships and ships other than passenger ships of 3000 gross tonnage and upwards constructed on or after 1 July 2002 must carry Voyage Data Recorders (VDRs) to assist in accident investigations, under regulations adopted in 2000, which entered into force on 1 July 2002.”

“The regulation requires a VDR, which may be an S-VDR, to be fitted on existing cargo ships of 3,000 gross tonnage and upwards, phasing in the requirement for cargo ships of 20,000 gross tonnage and upwards first, to be followed by cargo ships of 3,000 gross tonnage and upwards.

The S-VDR is not required to store the same level of detailed data as a standard VDR, but nonetheless should maintain a store, in a secure and retrievable form, of information concerning the position, movement, physical status, command and control of a vessel over the period leading up to and following an incident.”

The main purpose of the VDR is to record and store ship’s critical parameters. Information is stored in a secure and retrievable form, relating to the position, movement, physical status, command and control of a ship over the period and following an incident. This captured data can be utilised for “incident scene reconstruction” for the purpose of root cause analysis.

There is no principle difference between a voyage data recorder (VDR) and a simplified voyage data recorder (S-VDR).

The difference is the amount of information required to be recorded. The VDR requires more data to be recorded than the S-VDR.

With the presence of a Voyage Data Recorder, getting to the root cause of an accident becomes a possibility, when the recorded data is analysed. Of course, it takes an expert to carry out this analysis.

In the case of a ship sinking with all hands on board, the only evidence left behind is the VDR, as no one is available to be interviewed.

But where the ship does not sink and lives are not lost and the vessel has been part of or involved in an accident, the recorded data is extremely helpful in recreating the scenario that led up to the accident.

I am reminded of a Master (not a ‘Barber’ ship) who left Port Klang, heading for Labuan. He had to cut across the main traffic flow and join the stream of ships on the other side of the separation scheme. I have sailed on ships where many Masters wait patiently for, sometimes, even an hour or so to find a gap in traffic to cross over. On many such occasions I have gone out on deck and been awed by the heavy traffic.

In the incident I relate, I had inspected the vessel at Port Klang and had spent nearly 36 hours on board. There was a devil-may-care attitude amongst all, a nonchalance bordering on arrogance among the Russian and Ukrainian mix of staff. I left the ship with a feeling of unease as the ship left the berth.

It was 2 AM and the Master was in a hurry to cross the traffic and just kept speeding up. A small, 15,000 ton tanker, on its way to the Persian Gulf, collided with her, striking her exactly at midship, at almost a 90 degree angle.

The tanker was lucky that she sustained only stem and foc’sle damage, no pollution.

Our ship was lucky to be hit exactly at port midship where there was a void space, but also pierced the inner bulkhead, on the other side of which was one cellular hold for containers. Having been struck just about the water line, a little water would go into the hold whenever there was a bit of sea. Giving the vessel a slight starboard list ensured no water entered.

Had the impact been 4 metres aft, 200 tons of Diesel Oil would have been in the water. Had the impact been 4 metres forward, 400 tons of Heavy Fuel Oil would have been in the water. All a matter of a few seconds ahead or after.

I received a call about 30 minutes later in the hotel where I was staying and would have left soon. They asked for instructions. Port Klang was the closest and the agent procured them anchorage space.

Over the next 2 weeks, Class and P&I inspections took place and temporary repairs were carried out. Marshall Islands office in Hong Kong were informed. I got the written submissions of the persons on duty, all of them suspiciously similar.

Marshall Islands office sent their Investigating Officer about a week later, A Captain Greg Copley. What followed was a remarkable three days, where I observed an expert at work every step of the way.

Individual, probing, interviews of the three Bridge personnel (who were in attendance) made a mockery of their written statements, where two of them admitted that the Captain had drafted their reports. The Captain’s interview revealed an obstinate, arrogant nature, putting the blame entirely on the other ship.

The VDR tapes were downloaded and played. The recorded data from different sources were synchronised and, starting from 30 minutes before collision, every second was played out. It required translators as the language spoken was Russian.

The vessel was at ‘Half Ahead’ when an ARPA plot showed a good chance of collision about 10 or so minutes away, with the tanker at her full sea speed on an imaginary highway, with her requiring more time to reduce speed if she were inclined to do so.

I was told by Capt Copley that, although our ship had the right of way to a vessel approaching from the portside - according to Colregs - common sense, prudence and seamanship demanded that our ship continued on ‘half ahead’ for a while more to allow the other ship to pass ahead of us. It would been easier to adjust our vessel’s speed as we were still at manouvering rpm, while the other ship was not.

He had many more explanations but, on the whole, questioned the seamanship of the Captain. The Voice Recorder also showed a distinct arrogance of ‘that is his problem, not mine’ when advised on the Closest Point of Approach.

He speeded up to Full Ahead and collided.

The investigator attributed blame thus - 60% on our ship and 40% on the tanker. The Captain kept arguing but had to be sacked.

This is one small instance of how a VDR played a part in an investigation.

BNWAS : Bridge Navigational Watch Alarm System

Introduced at the turn of the century, it became a mandatory part of Bridge Equipment in 2011.

Basic structure of this equipment was to sound an alarm if not reset within a set time period. Something similar to a ‘Dead Man’s Alarm’ in the Engine Room, after UMS (Unmanned Machinery Spaces) had been introduced, it started off as a unit that needed to be reset within a certain time period to indicate that the Watchkeeper is alive and well.

It only took a couple of years before more ‘sophistication’ - an euphemism for more complications - was introduced into this simple piece of equipment, adding processes and connecting them to ‘Off Course Alarm’ and ‘Closest Point of Approach’ to sound an alarm.

The alarm sounds first on the Bridge only and, if not acknowledged within a set number of seconds, reached the other navigating officer’s cabins.

Does BNWAS give the needed license to shipping companies to scale down the ‘2 persons on the Bridge at all times’ mantra? If so, it would be a dangerous precedent.

The US Coast Guard, who set the guidelines for all US Flag vessels, sensibly, have been very specific in not allowing a ‘One Man Bridge’ for the larger vessels. It is the ‘Flags of Convenience’ that stretch the rubber band in reducing staff with ‘Minimum Manning Certificates’ and most Ship Management companies taking advantage of it.

This puts pressure on the Master and Mate. If they decide on a ‘Two Man Bridge’, they lose 3 men for deck maintenance during the day time.

If they decide on a ‘One Man Bridge’, they flout and skirt safety standards. Some hedge their bets by having a ‘One Man Bridge’ only during ocean crossings.

To their credit, very few Masters opt for this and swear on safety being paramount.

I, personally have had this apprehension towards a ‘One Man Bridge’, especially at nights after a particular incident on the ‘Citadel Hill’.

Due to large scale repairs and steel renewals taking place on deck, of which I was in charge, I needed a deputy and the Chief Mate was the right person for this. A new Third Mate joined the ship and the Chief Mate was taken off the 4 to 8 watch to assist me.

As was my habit, I would wake up early and find myself on the Bridge well before sunrise, where most Mates I have sailed with would have a mug of hot coffee ready for me, eagerly anticipating a conversation that would cover multiple subjects.

I continued going up to the Bridge for the morning coffee, even though the Chief Mate was off watch. One morning, we were coasting the US East Coast, merrily traipsing along at full speed, helped along by the coastal current, the Gulf Stream Drift, I went up for a coffee.

As I made myself a cup, I looked around and there was nobody on the Bridge. Which was not surprising as the Watchkeeper sometimes had something to do on the Bridge Wing or on the Monkey Island.

The radar showed no targets - this was before the days of ARPA - the course was as plotted on the chart. After ten minutes, I grew apprehensive and searched for the Third Mate on the wings and on the monkey island. Not finding him, I phoned, woke up and called the Captain up. The Third Mate was fast asleep in the Bridge toilet.

So, BNWAS, to my mind, was a welcome piece of equipment for the Bridge.

BNWAS in its Simplest Form

Add Ons to BNWAS

Complicating a simple alarm

The Echo Sounder

A sounding line - a marked rope with a weight attached to it - would be lowered in to the water till the weight hits the sea bed, the depth of water would be called out and the Master of the sailing ship would gingerly use his sails to inch forward as close to land as possible, before dropping anchor close to an unsuspecting fishing village lazing on the beach, either to only pick up fresh water and provisions or else plunder the village.

As shipping trade slowly increased in one area, the commercial businessmen who would profit from such a trade got together and came up with a set of rules for fair trade - the first in line of the multitude of ‘Chambers of Commerce’ that would follow in their wake. They were instrumental in clearing the path into the harbour - today’s channels - mapping and charting the low lying areas of the sea in close proximity to the harbour and introducing a ‘harbour pilot’ into the maritime matrix, to guide sailing vessels past the dangerous shoals and reefs. This continues to this day.

But they still depended on a sounding line to measure and call out the depths.

It was not until 1912, with the sinking of the ‘Titanic’ after having struck an iceberg, that engineers and scientists started researching the possibility of technically identifying an obstacle beneath, an impediment ahead.

In a primitive manner, man had known that sound travels through air as well as water, without knowing much about how to harness it for human needs.

Ancient Indian texts show that light and sound were known to be in a wave form and their approximate speeds were measured. But these findings drowned in the historical miasma of annexations, occupations, colonisation and the burning of libraries and texts, only for some remnants of ancient texts to show up in the 21st century.

1912 - and the sinking of the ‘Titanic’ - was a watershed moment for shipping in general in numerous fields as the more prominent scientists and engineers of that time turned their attention to solving a myriad of problems that shipping had accumulated over the centuries without any resolution.

Research into how sound waves could be used brought about the ‘SONAR’ - acronym for ‘Sound Navigation and Ranging’ - after finding that sound waves travel farther through water than light waves or radio waves, therefore exploring and mapping the ocean floor could be started in a crude form. As sound technology developed, it became more and more sophisticated and compartmentalised in as far as the ability to identify different underwater landscapes in 3-D, different life forms as in fish, different underwater mechanical naval submarines.

In fact, the sophistication to which sound research has reached has far reaching implications in various spheres.

The fishing industry of the more advanced nations has exploited this sophistication and, adding satellite technology to its arsenal, has depleted fishing resources during the last two decades to such an extent that entire species are now on the brink of extinction.

The military industry - mostly naval - has also benefited tremendously. The use of Sonar in submarine warfare has come to near perfection in simulated war exercises.

The Merchant Marine has belatedly used this technology for warning the ship about the depth of water below the keel.

"Basic Principles of Echo Sounder:

Short pulses of sound vibrations are transmitted from the bottom of the ship to the seabed. These sound waves are reflected back by the seabed and the time taken from transmission to reception of the reflected sound waves is measured. Since the speed of sound in water is about 1500 m/sec, the depth of the sea bed is calculated which will be half the distance travelled by the sound waves. The received echoes are converted into electrical signal by the receiving transducer and after passing through to stylus which burns out the coating of the thin layer of aluminum powder and produces the black mark on the paper indicating the depth of seabed."

Principles of the Echo Sounder

The principles were simple - to transmit a sound wave and measure the time taken for the wave to resound back from the sea bed, taking the ship’s speed into account. Later, other variables were added for salinity, temperature of the water etc.

The most significant advancements in this sphere came during the First World War, more to combat German U-Boats than anything else.

The spill over of this technology into the Merchant Marine came soon enough.

Starting from using quartz crystals to gain a ‘piezo electric effect’, where the crystal changes shape in the presence of an electric current to become acoustic, which produces the sound wave, the technology of acoustics for the echo sounder went into the UHF range. Sharper, clearer images became possible.

The basics and principles remained the same; the technology and instrumentation to deliver the effect transformed over the decades.

Sounding Out Marine Life

Echo Sounder

Multi beam Echo Sounder for Oceanography

A ‘Furuno’ Product now on some Bridges

The Aneroid Barometer and the Barograph

Perhaps the two instruments that have contributed the maximum to safe navigation have been these two.

The Aneroid Barometer has served mankind and shipping for nearly 180 years since its discovery in 1844. Barometer pressure dropping is synchronous with anxiety rising on the Bridge.

A barometer measures atmospheric pressure in units of measurement called atmospheres or bars. An atmosphere (atm) is a unit of measurement equal to the average air pressure at sea level at a temperature of 15 degrees Celsius (59 degrees Fahrenheit).

The two other instruments that measured atmospheric pressure were the Torricelli invented Mercury Barometer and the Storm Glass.

Courtesy Physics Stack Exchange - The Mercury Barometer

Courtesy Vedantu

Storm Glass : A storm glass is a type of barometer used centuries ago. A storm glass is a sealed glass container with an open spout, partly filled with colored water. If the water level in the spout rises above the water level in the container, observers expect low pressure and stormy weather.

Storm Glass

The Barograph : A barograph is a barometer that records the barometric pressure over time in graphical form. This instrument is also used to make a continuous recording of atmospheric pressure.

Since its invention in 1760, it has undergone several changes without losing sight of its original inventor’s design, that of transferring atmospheric changes of pressure to a stylus that records the changes on paper.

A barograph fitted with five aneroid capsules stacked in series, to amplify the amount of movement

Courtesy Dreamstime = The Graph shows a Vessel that that barely skirted a storm and sped out of the way

Digital Barometers:

Today’s digital barometers measure and display complex atmospheric data more accurately and quickly than ever before. Many digital barometers display both current barometric readings and previous one-, three-, six-, and 12-hour readings in a bar chart format, much like a barograph. They also account for other atmospheric readings such as wind and humidity to make accurate weather forecasts. This data is archived and stored on the barometer and can also be downloaded onto a computer for further analysis.

With digitalisation and the vast improvements in ‘smart’ technology both, the Aneroid Barometer and the Barograph, once the mainstay of a Master’s weather predictions, have now been consigned to the scrap heap of maritime history.

===== To Be Continued in Blog 117 =====