“OK Captain, she’ll pivot round the fender now: hard to port and slow ahead”.        Photo: JCB

Many of you will recall Hugues Cauvier’s excellent article on the pivot point in the October 2008 issue of The Pilot. Paul Butusina’s article covers much the same ground but due to the importance to pilots of understanding this elusive point I felt that it was well worth revisiting the topic. JCB

The aim of this paper is to add few corrections to the pivot point theory as it is presented in seafarers books, because  understanding the pivot point is such an important element of safe manoeuvring of the vessel.

Introduction

The pivot point of the ship turning is defined in seafarers publications more or less accurately as follows: The pivot point is the point which traces the turning curve of a ship. It is located in the fore section of the ship, abaft of the stem at 1/6-1/3 of ship’s length. However other factors such as acceleration, shape of hull and speed may all affect its position.

It should be noted that when at anchor the pivot point moves right forward and any forces acting on the hull, such as wind or current, cause the vessel to move about the anchor position or the point where the chain lies on the sea bed although a sudden change will initially cause the vessel to pivot around the hawse pipe.

The available literature on ship manoeuvring and handling does not cover all aspects of the pivot point in a systematic way since it is the point in the diametrical plan of the vessel or in the prolongation of this plan, around which the vessel swings on the trajectory which she describes. This trajectory can be a circle arch with its own centre of rotation on the traject (momentary centre of rotation) which can result in the pivot point being located outside of the ship’s shape.

At speed, a more accurate description of the pivot point is a Tactical Point of Turning (TPT) which is located at the point of intersection between the ship’s diametrical plan and the perpendicular from momentary centre of rotation.  This is important for ships’ operators because it gives some indications regarding the equilibrium of the forces acting on the vessel and consequently provides an indication regarding space swept during turning and the possibility to predict the ship’s orientation.

Movements of a vessel: Water Resistance and Pivot Point

It is important to remember the three degrees of freedom of a vessel (Fig 1):

1. Longitudinal, along axis X-X’

2. Transverse ,along axis Y-Y’

3. Swinging to starboard or to port.

To find PP position we will simplify the factors which affect ship’s handling to the mechanical physics although the hydrodynamic effects have a considerable importance.

During straightforward movement, water-resistance force is applied right on the stem, which creates high pressure in front and around the bow (fig.2).

The same effect occurs for astern movement but in both cases the shape of underwater hull is very important in determining the high pressure effect.

As soon as a controlled or uncontrolled horizontal force acts on the vessel the ship will start to turn and she will expose a larger section of the hull to the water flow. The peak of water-resistance and pressure will therefore shift from axe X-X’ to the geometrical centre of underwater hull section area perpendicular on the new direction of the movement and the direction of the water-resistance (R), could be anywhere between longitudinal axis, X-X’ and transversal axis,Y-Y’.

Depending of the direction of the movement, the vessel’s speed, hull shape, trim and heel, etc the application point of the water-resistance force will be in different points along the vessel, changing continuously during complex manoeuvres.

To analyse the influence of horizontal forces applied on the vessel (ie rudder & wind) we have to relate these forces to the water-resistance force where it acts. This force will be present as long as vessel is floating and moving. The arm lever of these forces is the distance between their supports and Water-Resistance Force.

The resultant effect of several forces acting on a stopped vessel can generate all three movements. For our purpose, the rotation and the sideway movement are considered. The rotation movement has a centre of rotation which is the pivot point where the fore and aft extremities of the vessel are turning with the same angular speed inside of ship’s shape in all situations.

Besides the pivot point, the vessel’s trajectory has its own centre of curvature called the Momentary Centre of Rotation. In fact all forces acting upon a vessel have, more or less, momentary effects in ship’s dynamic movement.

Water Resistance and Pivot Point of a vessel stopped

Considering a ship stopped in the water we can find a point situated near its mid length, from where if a tug pushed with a force F the fore and aft extremities of the ship will move with same speeds V1= V2 (Fig.3).

fig 3

The force F is applied on the same support as water-resistance force R. Its centre of application is the Centre of Water (Lateral) Resistance (CLR). The lever F -R is therefore zero and the ship will move from position 1 -2 without any rotation.

If equal but opposite forces are now applied equidistant from the CLR then the ship will pivot around that point (Fig 4).

fig 4

Returning to the situation in Fig.3, if the force (F) is moved slightly aft of the CLR then the resultant will be a sideways movement coupled with a slight ahead movement which will cause the ship to start rotating but in this condition the pivot point will be ahead and well outside the ship shape (fig 5).

fig 5

From position 2, if our force (F) is now applied further aft and on the starboard 1/4, the speed of rotation is increased but the forward movement is reduced and the pivot point moves closer to the bow of the ship (fig 6).

fig 6

Moving this force right aft onto the rudder area ( i.e. with a pod proplsion unit) the pivot point may move back within the ship shape (Fig 7).

fig 7

The bow thruster will have opposite effect of moving the effective pivot point to the stern of the vessel (Fig 8). Obviously these are very approximate locations but at least serve to help anticipate where the pivot point might be.

fig 8

Getting Underway

If the engine is now put ahead with the rudder amidships with two tugs pushing up with equal power equidistant from the CLR the vessel will start to move ahead and sideways (Fig 9).

fig 9

Due to lateral resistance RL and the longitudinal resistance RI a resultant water resistance force RT acts on the starboard bow. The pivot point moves forward in the direction of the movement and consequently the levers of F1 and F2 related to RT change and d2 > d1. In consequence V2 >> V1  resulting in an accelerating swing to port. Even with a short “kick ahead”, this increasing of rotation speed can be seen. The same effect of course occurs when a vessel in a tideway is stopped over the ground parallel to the berth and the stronger the tide the greater is the effect. It is important to note that in this scenario the pivot point may again move ahead of the ship shape.

Likewise, if a vessel is moored with a current from astern, the pivot point will be aft at the moment the lines are cast off and ship will start to want to pivot around the stern with the bow moving away from the jetty faster than the stern if 2 tugs are alongside pulling off with equal power.

Fig 10 helps to explain why bow thrusters become useless for turning a vessel as the speed ahead increases.

fig 10

As the thruster (T) tries to swing the vessel towards the jetty, the water resistance on the CLR increases and with such a small lever (d) there is virtually no turning moment.

If we take the same ship and berth it stern to tide ( or approach the jetty stern first) ( Fig 11) then the lever (d) is long and the vessel will swing readily.

fig 11

The “Donkey Effect”

One of the most spectacular examples of applying an external force upon a vessel and getting the opposite result to that expected (donkey-like) is the movement of the vessel when a tug is acting on the support of water resistance force against it (Fig12).

If the tug starts to push on a vessel moving  at speed in position M1 it cannot turn the vessel due to the short turning lever. She will drift to starboard but will maintain the heading as in position M2. As soon as the tug stops pushing in position M3, the vessel will start to turn towards the tug. She will continue to turn in that direction as is shown in position M4 until the forces stabilise and the heading stability is restored.

In real time trials with escort tugs this effect has also been observed when the tug stays pushing on the hull. This effect along with those explained  in Fig 9 are most important for pilots using tugs on a vessel making way through the water. The higher the speed the more pronounced the effect.

JCB

The following link is to Paul Butusina’s full research paper from which the above article was edited:

The unit has been developed to use advanced satellite communications to ease vessel traffic management. Safeport is looking at being able to deliver more accurate, secure and reliable navigation and positioning information to the pilot to ensure safer and more efficient navigation and berthing.

Vessels participating in the system share their planned routes and schedules with vessel traffic management, or request a route for them. These are then validated to ensure safe compliance with any rules, and that the piloted ship does not interfere with other vessels.

Sweeping in close to mountain tops, theapproach to Trondheim late in the evening is, to say the least, dramatic. By late May, being so close to the Arctic circle, it doesn’t really get dark at night and with the sun risen by 02.30 am thick curtains in hotel rooms are a must for those who want to sleep – not that sleep was much on my mind since this was the culmination of 15 months of writing, editing, submitting drafts for moderation by a (most distinguished) technical panel!

I was attending a conference to deliver a paper on ship-generated pressure fields, before the world’s most prominent and respected Hydrodynamicists.

The 2nd International Conference on Ship Hydrodynamics (STS 2011) was held in Trondheim from 18th to 20th May 2011. Organised by the Royal Institute of Naval Architects (RINA), the University of Ghent (Flanders Hydraulic Research Institute) and hosted by the Norwegian National University Marine Technology Department (NTNU – Marintek), the primary topic for the conference was Ship to- Ship transfers and associated operations, with a secondary focus on hydrodynamic interaction relating to vessels manoeuvring in confined waterways.

Trondheim itself is an old city, centred on a cathedral said to be over 1000 years old, being both a former capital city and the traditional seat of the monarchy. The main part of the old city is bounded on three sides by a wide sweeping river and, to the west, by the fjord.

The MARINTEK Centre sits near the top of a hill not far from the centre of Trondheim and the location affords a good view of the surrounding city, harbour and the fjord. However, for an altogether different, and much more commanding view of the university campus and the marine research facility it is necessary to take a short elevator ride to the top of the campus grounds where a rotating restaurant with exhilarating views provided the venue for a very nice conference lunch.

Early keynote speakers spoke on a number of issues relating to Ship-to-Ship transfers and lighterage but interestingly, some of these talks would not have been amiss at a marketing conference.

The main plenary sessions commenced after lunch on the first day, with speakers being allocated one of two conference rooms, depending on their area of specialisation. Naturally, my own inclinations were directed to the more ‘practical’ issues of ship handling in confined waters. By the end of the first sessions, what was becoming very apparent was the difference in emphasis between the academic theorists, who were essentially mathematicians and computer programmers, and those with, even limited, real ship experience. I must confess, the language used by the academics was almost (but not quite) bewildering, and the mathematics was awe inspiring – if virtually unintelligible, to a practical ship handler.

As proceedings moved on, the division between the two camps became increasingly marked, along with the realisation that there was a need to reconcile the two. I cannot begin to explain how frustrating it was for the pragmatists (Pilots, Ship-Masters et al) to try and explain real experiences to the theorists who sought to predict the forces acting between ships (and berths) with absolute certainty and precision. Any suggestion that ‘it’s not like that in reality’ was met with almost stunned disbelief. The simple fact remains that not all realities correspond with the ideal conditions found in a test tank, and not all shipping encounters can be neatly defined according to the idealised graphics generated when perfect algorithms are fed into mathematically perfect simulation worlds! Like it or not, there is a difference between what ‘should’ happen, and what does happen.

For me, a most telling point was raised when someone explained the mathematics necessary to calculate the forces generated when two ships come into close proximity – during a ship-to-ship transfer.

It was quite a revelation to learn that a super computer could calculate the momentary forces in 1.27 hours, whereas a standard laptop might take 24.3 hours. I couldn’t resist asking what use this was to a pilot who was faced with making instantaneous decisions without the luxury of waiting 24 hours for data that was based on a set of momentary, historical, parameters. My own experiences as a pilot and an investigating lawyer quickly settled on a number of potential issues for pilots. There is a sobering reality that, following an incident, pilots finding themselves in court may be faced with hydrodynamic experts who hold impressive academic credentials and can calculate forces perfectly and precisely – providing they have weeks, or months, to do so.

A paper by Gordon Maxwell (Warsash), on the practicalities of ‘manned-model’ training was well received  but he too confessed to being perplexed by mathematical modelling concepts that could produce fantastic results after the event.

Dr Jo Pinkster (PMH Holland) held the fort for the pragmatists,as did Dr Larry Daggett (US Corps of engineers) who  discussed issues surrounding widening of the Panama canal.

My own paper was delivered towards the end of the second day shortly before the conference broke for the evening’s entertainment (a wonderful organ recital in the Trondheim Cathedral followed by the conference dinner). It is fair to say that I received the only standing ovation of the conference and the absolute support of pilot colleagues from Hamburg, Rotterdam, Brazil and the US. Few realised how much work was going on in the UK aimed at simplifying and explaining practical dimensions of ship hydrodynamics.

I felt it necessary to make reference to the ‘perfect world’ of computer simulations, and brought up a few hard facts that any pilot will attest to and that is anticipating how the vessel will react then countering it before a situation even develops, something that no instrument, regardless of how sensitive it is, can detect. This is where the true skill of the pilot lies, in his ‘intuition’ and ‘gut instinct’,  all points raised by way of a challenge to the theoretical researchers.

The closing moments of my presentation turned into a general challenge when I asked ‘what good will your work be to the man on the bridge can he apply what you propose for practical benefit?’ I concluded, ‘if he can, then the eventual benefit of the conference will be the reduction of hydrodynamic incidents, fewer collisions and groundings, the saving of lives, livelihoods, beaches and the environment. If the conference can, at any time in the future, hold its hand up and lay claim to any one of those objectives, then it will be deemed a success’. It appears to be a challenge well made, and seriously taken on board for the future.

However, not all technical the papers presented by the theorists were lost on the pragmatists. Of particular note was the keynote speech delivered by Professor Odd Faltinsen, the elder, charismatic, academic of MARINTEK. His presentation was something of a history lesson and, at the same time, a warning to his contemporaries. Addressing the subject of computational fluid dynamics (CFD) he spoke of his early days as a computer programming mathematician and confessed that, even 20 years ago, the belief was that algorithms and CFD would eventually do away with any need for Ship-handlers and pilots. They would be replaced by computer programmes.

With the benefit of hindsight, Prof Faltinsen made three defining statements that the practical mariner might take heart from:

1) CFD may look convincing, but testing of results reveals a difference from reality, and testing [against the real thing] for verification is critical for validation

2) Computer prediction may be ‘pretty good’ but it is not, and cannot be, completely satisfactory

3) There will always be a need for experimental facilities and they will always need updating because there is always likely to be a difference between computer modeling and reality, no matter how good the computers and models are.

Somewhere in the melee of maths and models, pressure fields and power-graphs, numbers and suppositions, the two sides did find common ground by accepting that each was trying to achieve  the same end but by different means and that the theorists would always have to validate their work against the hard data that is the pragmatists staple diet.

I learned much, made some good friends who, good to their word, have stayed in contact and are keen to undertake collaborative research with a view to benefitting the man on the bridge, the marine environment and safety of life at sea. I look forward with some anticipation to the 3rd International conference on Hydrodynamics, currently planned to take place during 2013, in Panama, and would recommend attendance to any who feel inclined to raise the bar.

Peter McArthur

Every pilot’s nightmare is to fall off the ladder whilst boarding and although such incidents are fortunately very rare, tragically  pilot ladder falls result in 1 -2  deaths per year worldwide. Last February my London colleague, Jon Stafford fell whilst transferring his grip from the ladder to the gate opening in the ship’s bulwark. Fortunately he survived and he hopes that by sharing his experiences he might help increase the safety awareness of other pilots. The following first hand account by Jon brings the reality vividly to life!! JCB

It was a climb  of around 5 metres and I clearly remember how it happened. I got to the top of the ladder and having gripped one of the hand holds in the ship’s rail opening I let go of the ladder to grasp the other and before I got hold of the second hand hold I swung away from the opening, smacked against the ship’s side and that was it, I fell!

I remember looking down to check whether I was falling onto the cutter or into the sea. Fortunately the cutter had moved clear of the ship and was running parallel close to the ship’s side. I knew then that although I wasn’t to suffer serious injury from falling onto the cutter, but I was going into the icy  North Sea in February between the ship and the cutter!

As I hit the water my first thoughts were the propellers of first the cutter and then the ship. I knew that the coxswain would have stopped the engines when he saw me fall but the Captain wouldn’t have time to stop the ship’s engine before I was past and that really scared me. I went down quite deep but I could see the boat’s searchlight and the ship’s lights from under the water as the integral lifejacket in my SeaSafe coat inflated. When I resurfaced I was at the stern of the pilot cutter but the water flow was pushing me hard up against the ship’s side and I knew that it was taking me towards the ship’s propeller. As I slid along the ship’s side I was dragged right in underneath the counter so I tried to keep my feet up to keep my body on the surface.

I estimate that I passed within a metre of the propeller and although from falling to clearing the stern of the ship  couldn’t have been more than 20 – 30 seconds it felt like a lifetime!

Having got past that immediate danger I started to concentrate on recovery. All London pilots undergo training with our cutter crews, who hold regular exercises in  recovering casualties and I now have first hand experience, that  proves the training works really well. Remarkably my brain stayed crystal clear, concentrating  on staying alive.

I knew that my greatest risk now was from hypothermia so I worked at keeping my body heat in by keeping my legs together and jamming my cap down tight on my head.

I then started looking for the pilot cutter. It was dark and there was a bit of a swell running and  I could hear the crew talking to each other but then heard one state that he’d lost sight of me which caused me some concern!

I put my left hand up hoping that the retro-reflective tape on the jacket’s sleeve would improve my chances of being spotted. Fortunately that worked because as soon as I had raised my arm  I heard a shout and the boat came round and alongside me very quickly. The coxswain did it first time, closing  in and stopping the cutter in the perfect position for recovery. The crewman then managed to catch hold of me at the first attempt with the MateSaver pole, something that I know isn’t easy to achieve!

It was only when I was hauled aboard the cutter that  I realised that I’d injured my ankle.

Once ashore, there was a fast response paramedic, an ambulance and three police cars waiting to take me to hospital, where I was treated for mild hypothermia and informed that my ankle was broken.

The experience hasn’t put me off. Climbing a pilot ladder has a certain risk attached to it and falling off  is a foreseeable, but fortunately rare, accident for which we are trained. Using ladders is just part of the job and I now know that the extensive emergency training we receive really does work!”

Jon Stafford

The following letter throws a very interesting light on the facts of Charter Parties and pilotage which I believe is of interest to all pilots. The letter was originally published in the November 2010 issue of SeaWays and is reproduced here with the kind permission  of the Author and the Nautical Institute.   JCB

*******

It is a vexing issue that time charterers (voyage owners) do not acknowledge that a pilot is indeed a valuable resource in their safety chain. The New York Produce Exchange (NYPE) form time charter party, states:

‘The charterers, while the vessel is on hire, shall provide and pay for all the fuel except as otherwise agreed, port charges, all pilotages, towages, agencies … ‘

The Baltime (1939) Clause 4 states: ‘Charterers shall provide and pay for      pilotages (whether compulsory or not)’.

The intent of the printed NYPE and Baltime forms in relation to ‘pilotages’ is very clear under the time charter party contract -the charterer (voyage owner) will provide and pay for all pilotages without qualification. However, internationally reputable time charterers insist on inserting ‘compulsory’ before ‘pilotages’ in the NYPE and Baltime forms and deleting the words “whether compulsory or not” in the Baltime form. This contractually absolves the time charterer from employing a pilot at their cost.

The vessel while on time charter is ‘under the orders and directions of the charterer as regards employment and agency’ (Clause 8 NYPE C/P). While under the time charterers’ orders, the master is required to prosecute the voyage with all despatch, which includes taking the shortest available route (Hill Harmony). In areas around the Euro-Channel,    English Channel, North Sea, Skagerrak, the Baltic Sea, Marmara Sea and the such, the only shortest route to local ports is through these areas.

IMO recommends and encourages the use of pilots in these areas -IMO Resolutions A.480(lX) (adopted in 1975), A.620(15) (adopted 1987), A.486(XIl) (adopted 1981), A.579(14) (adopted 1985), A.668(16) (adopted 1989), A.827(19) (adopted 1995).

The inland Sea of Japan is equally hazardous particularly when a shipmaster is unfamiliar with the area; however the IMO appears not to have addressed a Resolution for it, where competent inland sea pilots are readily available.

Governments have also established VTS where, in their opinion, the volume of traffic or the degree of risk justifies such a service. VTS should be seen as a complementary service to pilotage.

The time charterer is a “disponent owner” for the duration of the time charter party, and being de facto ‘owners’ it is they who should do all that is necessary to prosecute their chartered voyage in both a physical and environmentally safe manner.

This begs the question as to why such readily available competent pilots are considered by time charterers as to be only a cost and not a benefit to the safety of their voyage. IMO Resolution A.159(ES.IV) [1968] ‘recommends governments’ organise pilotage services where they would be likely to prove more effective than other measures and to define the ships and classes of ships for which employment of a pilot would be mandatory’.

Alas, governments, for reasons of their own, despite having economic jurisdiction extending up to 200 nm from their State, do not appear to have found any good reason to encourage the use of qualified pilots. All pilots arrive at their position because of the authority granted through State based competent authorities.

Ship and cargo insurers and P & I clubs, should be comforted that their insured is in competent hands, through the ‘pilot’s advice’ supporting the ‘master’s orders’.

The shipping industry has always looked to pilots as being an integral component in the safety chain, adding skills and knowledge over and above that which is provided by the ship’s crew. If pilotage waters did not hold an additional element of risk, they would not be pilotage waters. It is axiomatic that a pilot should be employed by the ‘voyage owner’ for the safety of cargo and for the well-being of the marine environment. Charterers should be obliged to consider this as part of their responsibilities since the vessel is under their instruction for the voyage.

An arbitration on ‘liability for noncompulsory pilotage fees (9/80)’ concerned a dispute in relation to pilotage fees under a trip time charter on a NYPE form that expressed the usual printed clause 2. The master engaged a non-compulsory pilot and the owners paid the relevant fees. The owners sought reimbursement of the noncompulsory pilotage fees from the charterers. It was held that under the clear and express provisions of clause 2, the time charterers were liable for tbe cost of pilotage. (The word ‘compulsory’ was not inserted before ‘pilotages’.)

However the arbitrators did not touch on the fact that the master was under the instructions of the charterers as regards employment and agency. It was opined though: ‘Although the charter-party covered the situation. it was still a matter of reasonable prudence for a master of a foreign nationality responsible for a large and valuable sbip and cargo to engage a pilot for navigation in the English Cbannel’.

I am not aware of any further legal or arbitral decisions made on clause 2 of the NYPE and the Baltime 1939 form in regard to ‘non compulsory pilotages’, and the legal consideration of the charterer’s responsibilities ‘as regards employment and agency’.

Time charterers, shippers and terminals through their employment and promotion of ‘risk assessment companies’, purport to embrace the doctrine of safety by vetting the ship, the owner and manager. However by not employing a pilot during their voyage they are contributing to the risks to the marine environment and overall risks to the voyage, while the vessel is under their instructions for the voyage as ‘voyage owner’ littoral states.

The Nautical Institute and organisations such as BIMCO, IMPA, and signatories to the Antwerp Rules, should, for obvious reasons, take a closer look at ‘encouraging~ the use of available pilots by the ‘voyage owner’. In the meantime, should the time charterer voyage owner demand that they will only appoint and pay for ‘compulsory’ pilotages”, they should be made to be equally liable and responsible for any incident that might occur during their voyage requiring the charter party form’s true meaning and intent be radically changed.

Tbis point may well be legally debated, in relation to ‘contributory negligence’, should there be a major issue.

Ian Timmins MNI, ACIArb, FICS.

Sydney, Australia:

ACIArb: Associate of the Chartered Institute of Arbitrators

(FICS): Fellow of the Institute of Chartered Shipbrokers

There is a general misconception that ECDIS is entirely dependent upon the satellite Global Positioning System (GPS) to function but this is not the case since every ECDIS must be capable of being used to plot positions from any source be it visual bearings, radar or even stellar observations. The major problem to date is that on the majority of ECDIS currently on the market the manual option is not obviously available and not always user friendly and I have certainly yet to come across any navigator who has managed to plot a stellar observation on an ECDIS! Mind you it’s becoming increasingly rare to find any navigator who has plotted a position from a sun sight or stellar fix on a paper chart!

GPS has been fully operational with its constellation of 24 satellites for nearly 20 years and the developed world’s infrastructure is now almost totally dependent upon its constant availability so why would anyone bother trying to navigate without it? The answer is that GPS is so vulnerable that in many ways it is pretty miraculous that it works at all!

The signal strength from the satellites has been likened to someone in New York shining a 60 watt light bulb and someone in London having to see it, so it is not surprising that many are deeply concerned about developing back up systems to take over in the event of a GPS outage.

What might cause GPS outage?

There are several potential causes for GPS outage and the two most likely to affect shipboard GPS are sunspot activity and jamming.

Solar activity

The sun is always active in producing electromagnetic emissions which have the potential to disrupt GPS and historically this activity peaks and troughs in 11 year cycles. 2008 was the quiet trough and the activity is currently increasing again with the next peak anticipated in 2013. Alarmist stories of satellites being totally knocked out resulting in Armageddon for the developed world seem to be unfounded but, given the number of articles raising concerns over the effects of solar activity on GPS, it is evident that a quantifiable risk exists. GPS outage problems resulting from increased solar activity were anticipated for June but although I have read some reports of relatively minor positional errors of around 5m it seems that not all satellites are affected equally and I have been unable to find any reports of problems sufficiently severe to render GPS unusable so it is possible that the effects may not be as great as feared. Additionally, advances in receiver technology using the dual frequencies transmitted from the GPS satellites are also reducing the possibility of severe disruption. Only time will tell if this is really a serious threat but if it is then it is probable that the effects on the world’s shipping will be well down the impact list!

GPS jamming

In contrast to the solar activity, the jamming of the satellite signal is a real and very significant problem in that it generally results in the total failure of the GPS receiver. Jamming can be unintentional or deliberate but in either case it is always serious. An example of unintentional jamming occurred in  Moss landing, California where a faulty TV aerial amplifier blocked out GPS over the whole harbour area and there are other examples of faulty electrical equipment having a similar effect on GPS.

Currently in the USA there is a major scandal arising out of a start up broadband company called “Lightsquared” which has been granted a license to create a high power cellphone network to bring high speed broadband and mobile phone coverage to remote areas. The problem is that since its initial application for a license there were major concerns that the $14bn network used frequencies too close to the GPS frequencies which would interfere with the GPS signal. The license was granted on the condition that no such interference would be detected. However, the Government body responsible for granting the license (FCC) commissioned a test which revealed that GPS was seriously affected as per the following extract from a report on the trials:

“Last month, the National Executive Committee for National Space-Based Positioning, Navigation & Timing, and the Federal Aviation Administration tested the LightSquared systems and found them disrupting the signal strength to all GPS devices in the test area”.

In some tests, all GPS-based receivers including those used by the U. S. Coast Guard lost their ability to navigate. Some GPS systems used by space agency NASA for scientific use were also seriously impacted due to LightSquared’s service.

So, that would appear to be conclusive, or is it? The FCC hasn’t withdrawn the license ( this is a massive infrastructure project) but seems to be accepting assurances from Lightsquared that the problem can be resolved by technological fixes. The large opposition lobby group, the Coalition To Save Our GPS, has countered that the technical fixes haven’t yet been invented. At the time of writing this article the mess hasn’t been resolved and, as can be imagined, the “blogosphere” is running red hot over the issue. The lawyers are no doubt rubbing their hands with glee as well!

Deliberate GPS jamming

This is where the greatest potential for GPS disruption lies, especially in port and near coastal waters. The use of such jammers is mainly for criminal activity such as car and lorry theft and for avoiding road tolls but they can also be used to provide privacy in an office environment. Currently the laws are being updated all the time but generally such units are illegal to buy in the UK or to use but it isn’t actually against the law to own one! The fact is that these units are readily available and can be purchased for around £25 for an in-car unit with a declared range of 5 – 10 metres and around £100 for a high power lorry unit with a range of around 100 m. However, these ranges are misleading since such units can cause severe disruption over a much wide area.

In the USA in 2009 such a unit wreaked havoc twice per day with.. a two hour disruption to air traffic controllers’ monitors, failure of doctors’ emergency pagers, ATMs refusing to dispense cash, confused maritime traffic management and a cell phone blackout. It took two months to identify the source which was a lorry driver using a cheap jamming unit to avoid tolls on the New Jersey turnpike.

Although there haven’t been any such disruptions recorded so far here in the UK, many are concerned that as the tracking and monitoring of road users increases it is inevitable that such devices will be increasingly used. More serious is the potential use of jammers in a terrorist attack and consequently both the US and British Governments have conducted jamming trials to assess the potential disruption and this has included specific maritime trials.

Here in the UK two major trials have been carried out by the General Lighthouse Authorities (GLA’s) using equipment provided by the Ministry of Defence (MoD)

for the first trial the NLV Pole Star was used to monitor the effects of a directional jammer operating at 1.5watts placed on Flamborough head under strictly controlled conditions. The effects of this trial were dramatic resulting in:

Numerous alarms on the bridge

Erroneous GPS positions

Failure of GPS fed equipment

Erroneous information presented on the vessels ECDIS

Misleading information presented by the vessels AIS

Reduced situational awareness.

GPS track during the jamming trial. All GPS devices failed.        Image courtesy of Dr Alan Grant, GLA

One important aspect of this trial was to ascertain the effects of GPS jamming on a back up navigation system known as e-Loran which the GLA’s have been developing during the last decade. As anticipated, the e-loran input was unaffected by the GPS jamming so a further trial involving a wider group, including UK and EU Government representatives, was arranged off the Tyne in December 2009 using the THV Galatea. These trials confirmed the findings of the Pole Star trials with both the on-board GPS and the hand held portable devices carried by the visitors being rendered useless. The on board ECDIS had been set up to receive the  e-loran signals and again this system was unaffected with a positional accuracy of within 9 metres being achieved throughout the trial.

The e-LORAN track during the jamming trial.           Image courtesy of Dr Alan Grant GLA

E-LORAN

All of you will be familiar with the Long Range Navigation (LORAN) system that was developed in the USA during WW2 based on the British GEE radio navigation principle. Using long wave transmitters LORAN had a range of around 1200 miles but whilst useful in open ocean it was never sufficiently accurate for reliable position fixing in coastal waters. The arrival of satellite navigation in the 1980’s saw a gradual decline in LORAN usage and the arrival of GPS in the 1990’s basically rendered it, along with the Decca navigation system, obsolete. The Decca system was shut down in 2000 but the LORAN chains were maintained.

Recognising the importance of a totally independent back up for GPS, work was undertaken to make LORAN sufficiently accurate to provide a back up for GPS and the result was an Enhanced LORAN or e-Loran. In the UK the importance of a system independent of GPS was recognised by the Government and in 2007 the DfT awarded the GLA’s a 15 year contract to provide and maintain e-LORAN. Other EU countries along with Russia and a few Far East countries have also agreed to maintain funding and there are currently 16 transmitters with coverage being particularly comprehensive in the seas around Europe and the Mediterranean.

In contrast to the UK & Europe, in the USA, somewhat surprisingly, the arguments in favour of e-LORAN have been rejected and in 2010 the USA chains were shut down and are being dismantled, all to save just $20m per annum! The US Defence Department’s solution to the problem of jamming is apparently to create a smartphone “app” that will detect GPS jammers which the public will be asked to download and leave running. It is anticipated that this will create a high density network to quickly identify the jammers! I did check to see if the article reporting this was dated 1st April because surely if  GPS is jammed a smartphone won’t work?

Although the UK and Europe have been supporting e-LORAN, so far there aren’t many combined GPS/ eLORAN receivers available and so far as I am aware no ECDIS manufacturer is offering e-LORAN as part of their installation.

ECDIS & Radar alignment

In part 3 ( issue 302), I suggested that, where a radar overlay is incorporated into ECDIS it should be perfectly feasible in the event of the failure of GPS input for an “intelligent” ECDIS to recognise a coastline’s features and align the ENC to the radar input. Although I am not aware of any systems that can perform this automatically, it has been pointed out to me that manual alignment of the ECDIS to a navigational feature such as that provided by radar overlay  is actually a requirement contained within the ECDIS performance standards and I understand that at least one manufacturer is working on automating this function.

Back to the plot!

As previously mentioned, all ECDIS can be used for plotting bearings taken visually or from radar but there are three major problems associated with this.

Firstly, the vast range of ECDIS operating systems means that there isn’t a standardised procedure for manual plotting so instead of a simple button on the screen marked “manual plotting” that would bring up a set of standardised and familiar plotting tools, the facility is generally hidden in a sub menu and even once found may not be logical to use. The good news though is that once located and understood, manual plotting on an ECDIS is far quicker than on a paper chart. Taking the manual plotting facility further, ECDIS would provide an ideal platform for including different chartwork tools such as a vertical sextant angle. The ECDIS database knows the height of all objects and the height of tide at the time of the observation. The navigator takes the vertical sextant angle, enters it in and “click” a range circle appears around the object and an ECDIS could also easily combine that with the echo sounding to highlight an area of position probability. Simple, it’s what computers can do!

The small screen size means that the navigator may have to scroll and zoom the display to find the land or sea marks being used for the position fix, a factor that I found particularly frustrating when I did the ECDIS course. Zoom out and the names, or even the marks themselves might disappear, zoom in and you have to hunt around to find them. The good news here is that large chart displays are gradually appearing on the market although the bad news is that many ECDIS only vessels have dispensed with the chart room so there’s now nowhere to locate a large horizontal display!

Conrac’s digital chart table

The third and probably most crucial factor is mindset and experience. Most of the traditional chartwork skills have been lost even with paper charts since the advent of GPS with many of the latest generation of navigators having got into the bad habit of just plotting the latitude & longitude from the GPS display onto the chart. ECDIS compounds this problem by showing a reassuring dot where the ship is and when the GPS signal is lost the ship will continue to update its position in Dead Reckoning (DR) mode and there is a recognised problem of a reluctance by some navigators to accept that this may not be where the ship actually is! This factor is compounded by the failure of the alarm systems on ECDIS to seriously alert the navigator that the GPS input has failed. The GPS failure alarm sounds the same as any other ECDIS alerts so it is very easy for a navigator to merely accept the alarm and take no further action. What I believe is required is a large red warning to be placed on the screen stating that the GPS has been lost and that the ECDIS is operating in DR mode which, even when acknowledged will reappear on the screen at regular intervals. Another alert could be set to appear if no manual position has been input at intervals determined by whether the vessel is in open or coastal waters or even better, have the magic ship position circle replaced by a flashing red “lost position” symbol similar to the lost target function on the radar.

Conclusion

The myth that if GPS fails the ECDIS becomes unusable has largely grown out of the manufacturers’ concentrating on GPS as the input and failing to provide the navigator with simple, easily accessible alternative positioning options However, with a back up such as e-LORAN, the potential need to for resorting to manual plotting will be reduced and further non GPS positional accuracy could be achieved by including the increasingly available Inertial Navigation Systems into ECDIS.

How missiles do it!!

Whilst researching this article I came across the following explanation of missile guidance from the US Airforce which I couldn’t resist including!

The missile knows where it is at all times. It knows this because it knows where it isn’t. By subtracting where it is from where it isn’t, or where it isn’t from where it is), it obtains a deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn’t, and arriving at a position where it wasn’t, it now is. Consequently, the position where it is, is now the position that it wasn’t, and it follows that the position that it was, is now the position that it isn’t.

In the event that the position that it is in is not the position that it wasn’t, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn’t. If variation is considered to be a significant factor, it too may be corrected. However, the missile must also know where it was.

The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn’t, within reason, and it knows where it was. It now subtracts where it should be from where it wasn’t, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn’t be, and where it was, it is able to obtain the deviation and its variation, which is called error.

Hmm! I wonder what Captain Cook would have made of that?          JCB

You may not be aware, but travelling with Inflatable Lifejackets on board aircraft can be difficult due to the fitted CO2 gas cylinders. These are classed under the International Air Transport Association (IATA) Dangerous Goods Regulations and require you to get approval from the operator before taking them on board. This means that you MUST contact your operator in advance of your flight or booking and clarify with them their position on the carriage of Lifejackets fitted with CO2 gas cylinders.

SEASAFE & Crewsaver Lifejackets and their components conform to current legislation as laid out by IATA guidelines.

1. Will not blast until a pressure greater than 540 Bar.

2. Each cylinder is pressure tested to 250 Bar.

3. Each cylinder is filled at a temperature of 30o centigrade to a pressure

of 100 Bar.

Additionally, If you fly with Easyjet, call 00 44 (0)8431045000 regarding carriage of any lifejackets containing CO2 bottles as hand luggage on planes. They will register your request against the booking reference number and in addition will e-mail you with a query/incident number as confirmation. The Check-in personnel and security should then be aware of the compressed air bottle on the booking reference and hopefully you will have a trouble free passage through the airport.

You should also consider registering your Personal Locator Beacon if carried.

All participant members of the group where present plus a number of observer members.

Following the fallout after the attempt by EMPA to forward the EPSBLAN proposal to IMO without consulting IMPA, the working group co-ordinator Maarten Betlem unfortunately resigned from the position. The meeting was therefore chaired by Norwegian Pilot, Stein Inge Dahn, a member of the working group from its inception. A number of important items were raised during the conference, which had possibility to be of concern for Pilots.

Efficient Sea Network: A report was given by German Pilot Albrecht Krammar about the Efficient Sea Net conference which had been held onboard a Swedish Ferry in January.

E-navigation: A long discussion took place around this topic.  It now appears that having decided that the e part of the title is only a prefix (and therefore does not stand for electronic, enhanced or even easy!) there is now some concern about the navigation part of the title.  From the discussion we had it would probably be better to think of e-navigation as e-Information exchange! IALA consider that Portable Pilotage Units (PPU) aren’t part of e-Navigation. However, since some authorities are extensively using PPU this position is inexplicable.

S Mode: is now being talked about as ‘Default Mode’. This may not appear to be of consequence but it shows how when something such as S-Mode is rejected within a democratic forum, its supporters will attempt to introduce it by another means.

Shore based Pilotage.: Albrecht Krammar reported that the Norwegian Coastal Administration are determined to move towards the concept of monitoring navigation from ashore.

Standards of Passage Planning:
This is another area where non-Pilotage bodies, including flag states are trying to influence the way that pilots conduct their work assignments.  There is an unfortunate trend to try to find a “one size fits all” solution to any situation.   The Bahamas Maritime Authority had a paper presented to IMO for discussion at IMO Nav 57 titled “ Navigational accidents whilst under pilotage”, this paper impinges very heavily on the way that pilots conduct their duties.

E-nav Port State Bridge Local Area Network (EPSBLAN): Since its first meeting, one of the most time consuming topics for the EMPA e-Navigation working group as been the concept of EPSBLAN. The original statement from the working group was:

We suggest that EMPA and IMPA as a part of their e-Navigation strategies should initiate the development and implementation of a new wireless interface protocol on the bridge of all SOLAS vessels, the EPSBLAN.

The supporting arguments for this came from:

Whereas the AIS Pilot Plug is a one-way, low-bandwidth cable interface that only relays data that is available in the AIS instrument, the proposed EPSBLAN interface should be a two-way, broadband, wireless interface allowing for effective and comprehensive exchange of information between all navigational systems on board with the members of the Bridge Team on one side, and of the Port State representatives (Maritime Pilots, Port State Control officers, etc) and their portable equipment on the other side. The EPSBLAN concept is not rocket science. On the contrary, all ships today are equipped with marine data network for communication between on board marine electronic devices. The US based National Marine Electronics Association has developed protocols for such communication networks. Implementing a wireless interface to these data communication networks that allows for “visiting systems” (e.g. a PPU) to connect,should consequently not be regarded as a technical challenge, but more as a political one.

Much discussion took place to prepare a paper outlining the benefit of, and the need for some type of two-way exchange of information.  Unfortunately there was an error of protocol and the EMPA paper was passed to IMO directly and not through IMPA.  A further error took place whereby the paper was probably not subjected to sufficient scrutiny and therefore the potential full implications were not appreciated by all.

Consequently it was necessary for the EMPA e-Navigation working group to revert to all EMPA members with a document laying out the full details of the EPSBLAN for comment about if and how it was to progress.  An impact assessment inquiry was sent to all EMPA member associations on May 9^th 2011.

The result of the ballot was split 6-5 in favour of rejecting the EPSBLAN project.

Although Dave Williamson, Peter Wylie and myself (on behalf of the UK) had fully supported EPSBLAN throughout, the UKMPA, after discussion through section committee’ rejected the proposal.  This did not cause any problem for me personally and I was comfortable at the meeting of May 24^th to explain the position of the UKMPA.

Much discussion within the meeting followed which acknowledged that IMPA must be the pilots’ representative at the IMO and that since all members of EMPA are also members of IMPA we must speak to the outside world with one voice.  It is good that we have frank open discussions within our own forums but we must present an internationally agreed “position” to the IMO.

At this stage it was felt appropriate to consider if there was a desire or even a need for the EMPA e-Navigation working group to continue.  There was overwhelming support for the need to continue the group.

The next major task the group has decided to tackle is the carriage and use of PPU.  A survey will be carried out to try to identify all different equipment being carried and to evaluate where it fits into the legal requirements of  Pilotage.

Canadian Pilot and IMPA Vice President Simon Pelliter is an observer to the working group and it was agreed to hold the next meeting in November when Simon will be in Europe and available.

A budget figure of 12, 000 Euros has been set aside by the EMPA board for continuation of the project.

Kevin Vallance

WMA have invested around £2.7M and have moved their manned model facility to a new purpose built site, after 31 years operating at Marchwood and in June the UKMPA were invited to the one of the opening events so on the 16th June despite an early rain shower, 5 committee members took the opportunity to explore the new facilities in 3 of the models and put their shiphanding skills to the test!

The Timsbury Lake incorporates the experience gained from the many years operating manned models at Marchwood and brings manned model training into the 21^st Century with new purpose built classroom facilities incorporating the latest ‘SMART’ board technology.

The new lake is similar in size to Marchwood (around 10 acres) however the shape is elongated and includes a number of harbour basins and a purpose built canal. The new berths are a mixture or ‘open’ and ‘solid’ berths which offer a huge variety of berthing options. Importantly, WMA also owns the 15 acres of mature woodland surrounding the lake, which helps hugely to mitigate the wind effects on the lake since, due to the model scaling, the wind effect on a 1/25^th scale model is increased by a factor of 5!

Timsbury Lake is shallower than Marchwood and ‘weed free’ due to the turbidity of the water. The lake is fed by a number of streams from a large catchment area and the level of the lake remains constant. There is some current flowing through the Lake, which varies depending on recent rainfall and some counter currents have been detected. All in all the lake is proving to be more challenging than Marchwood and has great potential.

Historically the Lake dates back to the 9^th Century when monks from Winchester constructed the dam and used the lake as a source of fresh water fish and later a medieval mill was powered by the water run off from the Lake. In more recent times the Lake has been used for ‘fish stock’ with numerous bunds having been constructed and has been a haunt for carp anglers. These bunds now form the many harbour areas within the Lake.

The planning process was reasonably straightforward and incorporated the latest control measures to protect the environment and the fascinating ecology found at the lake.

Timsbury Lake ran the first course on the 2^nd May and an Open day was held on 21^st/22^nd June for the official opening. Feedback from returning students has been extremely positive and the ‘old Portacabins’ have now been demolished!

T&TC Chairman Jonathan Mills (Medway) pilots ‘Endeavour’ round the Horseshoe bend shaping up for the Top end of the Canal with Nick Lee (London) at the controls.  Photo: Nigel Allen

Further information on the lake:

www.mannedmodels.com