Underwater Technology Vol 18 No 1

Spring 1992

A Personal View

Subsea Technology – Opportunities for the Offshore Industry

JRS Morris CBE

Technical Papers

Encouraging Future Young Scientists – The View from One Research Laboratory

PA Hollow

Abstract: The Institute of Oceanographic Sciences Deacon Laboratory has been setting up links with schools to encourage pupils to consider careers in science and technology.  Initiatives have included school science projects, the supply of information for teachers, work experience for pupils and the publication of careers advice.  The need for such education links arose during the late 1980s and this article examines the background to this.  It describes the activities of the past two years and concludes that although assessment of these activities is difficult, the potential encouragement to young scientists is very valuable.


Day–to–Day Impact of Salmon Farming on the Work of the River Purification Boards

H Smith

Abstract: This paper is an attempt to clarify the role of the river purification boards in Scotland and to explain how legal control of the salmon farming industry was developed.  Estimates are made of the potential polluting impact of an industry that has grown dramatically over the last decade.  The author also identifies the pollution pathways arising from the industry, and differentiates between operations at land–based farms and floating cage farms.  Details are also given of the Clyde River Purification Board’s control policy and the self–monitoring requirements imposed on fish farming.  Finally, the author makes clear how the self–monitoring required by the boards relates to the charging schemes levied by all the boards on all discharges in respect of compliance and environmental monitoring.


Estimation of Extreme Wave Heights: A Review of Guidance Issued by the UK Department of Energy

N Hogben & DJT Carter

Abstract: The paper reviews the guidance on estimation of extreme wave heights issued by the UK Department of Energy in 1984 and 1990 with emphasis on the derivation, not previously published, of a key formula quoted but not explained in the 1990 issue.  It considers first the widely used simple approach underlying the data and associated guidance issued in 1984, and the reasons for the change to the different presentation based on a more complex analysis of the 1990 issue.  It then explains the 1990 analysis and discusses its implications in terms of a comparison between the 1984 and 1990 data charts for European waters.  A main finding of the paper is that due to fortuitous balancing of differences, the simple approach of 1984 and the more complex 1990 methods yield very similar results.


Advanced Power Systems for Autonomous Unmanned Underwater Vehicles

JG Hawley and GT Reader

Abstract: The underwater scientific, commercial and defence communities have long been aware of the potential uses of unmanned Autonomous Underwater Vehicles (AUVs) and the development of miniature high capacity computers and artificial intelligence systems has allowed more ambitious missions to be considered for such vessels.  However, to carry out these envisaged tasks new power systems will be required which are superior to those currently used in non–nuclear underwater vehicles.  Existing systems, almost exclusively, use lead–acid battery driven electric motors and the energy storage capacity of these systems is only sufficient for short reach missions.  Consequently, alternative power systems are being developed which make use of advanced batteries, fuel cells, semi–cells, radioisotopes and non–air breathing heat engines.  This paper details the power requirements for AUVs, examines the advanced power systems that are being developed for use in such vessels and describes the driving forces behind their possible realisation.


Physiological Monitoring by Underwater Ultrasonic Biotelemetry

B Woodward and R Sh. Habib

Abstract: Underwater ultrasonic biotelemetry is a branch of underwater technology concerned with the transmission of physiological information from a human or animal subject to some remote receiving station.  Here, we consider the transmission, reception and processing of signals from swimmers and divers, which includes signal formatting, multiplexing and encoding, transducers and power amplifiers, power sources, decoding and data analysis.  Applications include monitoring the heart rate, breathing rate and temperature of a patient in a swimming pool or a free–swimming diver in open water.  The most challenging problem addressed is how to transmit an electrocardiogram (ECG) signal in the severe multipath environment of a swimming pool.

Meeting Reports

Ocean Opportunities – Management for the Future (An address given at the SUT AGM, 12 December 1991)

Admiral Sir Lindsay Bryson


Advances in Diving Technology to 50 metres—Report on Seminar

M Johnson

Book Reviews

Marine Minerals in Exclusive Economic Zones, by DS Cronan

Reviewed by AJ Smith

Ocean Variability and Acoustic Propagation, by J Potter and A Warn–Varnas (Eds)

Reviewed by ML Somers



Underwater Technology Vol 18 No 2

Summer 1992

A Personal View

Industry now values collaborative research

T Veness  

Technical Papers

On–Site Tests for Underwater Video Picture Quality

RW Barrett, M Clarke and B Ray

Abstract: The majority of underwater operations involve the use of video for observing and recording.  This paper presents the results of a multi–sponsor project managed by The Marine Technology Directorate Ltd.  The objectives of the project were to develop a set of test procedures and quality acceptance thresholds to ensure that underwater videos shot on site will be fit for their intended purpose.  The tests were designed to be used and interpreted on site by non–specialist personnel.


Control System Design for High Pressure, High Temperature, Subsea Control Systems

M Theobald, M Fabbri and D Kirkman

Abstract: This paper examines the problems associated with subsea control systems when dealing with high pressures and temperatures.  It offers some overall design consideration to reduce the impact on umbilicals.  Key subsea components such as control valves and hydraulic connectors are examined in detail.  The authors conclude that existing design can be modified to withstand foreseeable higher pressures (up to 150°C).  The recommendation is made that long–term testing is carried out to prove key components.


Downhole and Subsea Completion Design for a High Pressure North Sea Gas Condensate Field

S Gomersall, K Sardar and G Rae

Abstract: This paper details the overall system design for a 15,000 psi subsea, gas condensate well in the North Sea.  Currently, significant industry interest exists in the technology required to complete wells of this type, which would enable substantial hydrocarbon reserves to be developed.  Subsea wells such as this have not yet been completed.


Engineering Technology and Aquaculture

MG Poxton

Abstract: Much of the information currently available on engineering technology for aquaculture is inadequate, having been empirically developed on a more or less trial and error basis.  Today, aquaculture remains an art with success largely resulting from the innate abilities of staff expert at animal husbandry, practising in open–water systems with good water quality.  The present state of the Atlantic salmon industry in Scotland – with over–production, low market prices, deterioration in environmental conditions, disease and many other problems – was both predictable and predicted.  However, this situation also applies to the production of salmon and other species in other countries, and is therefore regarded as a ubiquitous characteristics of the industry.  Before this situation can be improved, scientific and engineering technologies must be integrated and applied over a wide and diverse area.  Probably no single institute can muster enough resources to answer all the questions posed by this industry, indeed it probably would not be cost effective even to try to do so.  Consequently, collaboration is essential between scientists, engineers, economists and others from a wide range of institutions, together with the active participation of industrialists with sufficient financial resources to sustain long term programmes.

Meeting Reports

Subtech ’91—Back to the Future—Report on Conference

RG Birse, S Cardno and WE Mason


Automation of Remote Subsea Intervention—Report on Conference

J Turner


High Pressure/High Temperature Subsea Production Systems—Report on Seminar

GS Bonner

Book Reviews

Business Fundamentals for Engineers, by Chengi Kuo

Reviewed by RL Allwood


An Introduction to ROV Operations, by G Last and P Williams

Reviewed by DW Hartley



Underwater Technology Vol 18 No 3

Autumn 1992

A Personal View

Time for a Sea–Change in Engineering?

Prof JB Caldwell

Technical Papers

The Use of Exploration Geoscience Data in the Planning and Execution of Site Investigations for Offshore Development Facilities

MR Cook, JM Square and AW Hill

Abstract: Prior to development of an offshore hydrocarbon field, large sums of money are spent by operating companies on the acquisition and processing of exploration geoscience data.  These data, augmented by other publicly available data, can be cost–effectively integrated and reviewed to aid: field development conceptual design; selection of suitable sites for development facilities; and planning of detailed, site–specific, geotechnical and geophysical site investigations.  This paper illustrates the range of geoscience data that normally exists and the uses to which such data can be put.  A case history of two field development sites in the southern North Sea is presented, to emphasise the benefits of such a data review and the pitfalls that can occur if such a review is not undertaken.  The benefits of multi–use of existing data are summarised.  Recommendations are made for future geoscience data acquisition to provide further information for subsequent field development site investigations.


SWATH Vessel Engineering Science—State of the Art Seakeeping

T Downs

Abstract: Small Waterplane Area Twin Hull (SWATH) ships are an excellent example of how the physics of fluid flow is being exploited by naval architects: fluid/body interaction is engineered to the advantage of the ship.  They are a new breed of advanced ships receiving worthy attention.  The paper provides an overview and introduction to the principles of why SWATH ships behave as they do and how engineering scientists use frontier techniques to analyse them and produce design solutions.  The Navatek I, a Hawaiian passenger cruise vessel launched in 1990, is used as a case study for the ‘state of the art’ SWATH ship.  The aspects covered include motions, resistance, stability, seaworthiness, manoeuvring, structure, safety and missions.


Alternative Methods for Carbon Dioxide Removal in Diving Life Support Systems

R Hughes, DR Acharya and K Li

Abstract: The main objective of this investigation was to develop alternative, more efficient systems for carbon dioxide removal for diving operations and for small submersibles.  The methods studied included the use of absorbent liquids supported on porous solids which provided a regenerable system, and diffusion/permeation processes including, a) flat sheet membranes, and b) the use of hollow fibre permeators for gas separations.


Predicting the Fate of Oil Spilt at Sea

MV Leech and MI Walker

Abstract: Oil spilt at sea has the potential to cause signficant environmental damage.  In order to respond adequately and minimise such damage, it is essential to respond as quickly as possible.  The physical properties of oil undergo rapid changes once in the sea and many countermeasures are only useful for a short period of time before weathering processes make it difficult to deal with the slick.  Oil spill models have been developed to help speed response and to assist in pre–planning contingency efforts and training purposes.  Models can rapidly predict the movement, spreading and oil properties of a slick in the sea, providing advance warning to the authorities and helping to decide the most appropriate response.  This paper outlines some of the techniques behind oil spill modelling, concentrating particularly on the EUROSPILL model.  It is important to note that oil spill models represent an attempt to numerically simulate complex physical processes and are inevitably limited in their ability to predict the outcome of actual spills.  The quality of results from a numerical model is strongly influenced by the quality of the underlying algorithms and the quality of input data.


A Review of Equipment and Procedures for the ‘Lost Bell’ Situation

K Williams

Abstract: Diving bells are used extensively in the offshore industry for installation, inspection and maintenance of underwater structures and equipment.  The most dangerous scenario that can occur involving a bell is when it is impossible to bring it to the surface, either because the lifting system is broken or because the bell is trapped.  If the supply of breathing gas or heat from the surface has also been lost, then this is referred to as the ‘Lost Bell Situation’. This paper briefly looks at the factors which affect the life expectancy of a diver in this situation, and studies the current methods of rescue from a lost bell.  Alternative systems, which would reduce the danger to the divers and prolong their life expectancy are discussed and recommendations are made to facilitate their implementation.

Meeting Reports

Subsea Control and Data Acquisition—Report on Conference

R North

A Review of Current Developments in Offshore Ropes—Report on Conference

RL Allwood

Book Reviews

Water Baby—The Story of Alvin, by Victoria A Kahar

Reviewed by J Bevan

Tsunami Hazard: A Practical Guide for Tsunami Hazard Reduction, Ed. EN Bernard

Reviewed by D Pugh



Underwater Technology Vol 18 No 4

Winter 1992

A Personal View

The Pressure to Remain Ignorant

Dr Maurice Cross  

Technical Papers

Problems Associated with Seismic Facies Analysis of Quaternary Sediments in the Northern UK Continental Shelf

MS Stoker, FS Stewart, MA Paul and D Long

Abstract: Seismic facies analysis is increasingly being used in the interpretation of high–resolution seismic reflection data.  Existing depositional systems models, based primarily on seismic data, have been constructed on the basis that acoustic character can be directly correlated with relatively consistent lithologies and geotechnical properties.  However, borehole and shallow core data from the northern UK continental margin indicate significant inconsistencies in the use of the technique as a predictive tool.  Changes in acoustic texture can occur laterally and vertically, in both lithologically homogeneous and heterogeneous sequences.  Conversely, acoustic homogeneity does not necessarily imply a uniform sedimentary sequence.  The successful application of this technique can only be achieved by the integration of seismic data with other subsurface information, with interpretation based on sound geological concepts and models.


Oceanographic Equipment and Instrumentation: needs, trends and priorities

CP Summerhayes and D Girard

Abstract: Taking out the effect of inflation, oceanographic ships are now twice as costly and instrument systems are 10 times as expensive as they were 20–30 years ago.  The trend will continue as oceanography becomes a global science, and as the proposed Global Ocean Observing System (GOOS) becomes operational.  The growing requirement from all quarters for knowledge about the 70% of our planet that is covered by water demands increased investment in ever more complex and costly measuring systems.  To address the challenges of increased cost and complexity of operations and equipment, oceanographers must band together nationally and internationally to ensure that the slim resources available are used to best effect.  Collaboration is happening through bilateral agreements, through the design of large scale experiments like WOCE (the World Ocean Circulation Experiment) and the Ocean Drilling Programme (ODP) and through the planning of large scale operations, like GOOS.  Collaboration is fostered through the funding of Community Research Projects nationally, eg, by the Natural Environmental Research Council (NERC), and internationally, eg, via the CEC’s Marine Science and Technology (MAST) programme.  But more cooperation and better planning is urgently needed at the international level to reduce the rate of increase of operational and developmental costs and to get a maximum return of data and interpretation for the original investments.  High cost systems development is beyond national capabilities for the most part, requiring international cooperation and funding.  Discussions are needed in international forums (eg, Pan–European) to develop concensus and plans for collaborative action.


Evaluation of Hotspot Submarine Hydrothermal Mineralisation: the example of Pitcairn Island

DS Cronan, RA Hodkinson and O Stoffers

Abstract: A wide variety of state–of–the–art oceanographic survey, observation and sampling techniques have been employed to assess the marine mineral resource potential of the Pitcairn Island EEZ.  Results show that two large, hot–spot related, shallow submarine volcanic edifices occur some 80 km east–southeast of Pitcairn Island.  Both are covered by extensive hydrothermal mineral deposits, with one currently discharging hydrothermal fluids.  Studies suggest that sulphides may be buried just below the surface of the seamounts.  Many of the older seamounts within the Pitcairn EEZ are covered with relatively thick hydrogenous Mn–crusts.

Technical Note

High Pressure/High Temperature Reservoirs—an evaluation of the subsea control system problems

M Theobald and P Turner  

Meeting Reports

New Breathing Performance Standard for the Diving Industry—Report on Seminar

DE Elliott

14th International Congress on Acoustics—Report on Conference

B Woodward

Book Reviews

Management of Drilling Operations, by Ken Fraser

Reviewed by PA Strong

Dynamics of Fixed Marine Structures (Third Edition), by NDP Barltrop and AJ Adams

Reviewed by J Witz