Northern (High)Lights: Peter McArthur (Norwest Interaction Ltd)

 

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

 

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