Underwater Technology Vol 26 No 1

A Personal View

Who should bear the cost of quality?

R Pond

Letter

A regional initiative to manage the Bay of Bengal’s coastal and marine environment and its living resources

P Verlaan

Review

Lander techniques for deep–ocean biological research

PM Bagley, IG Priede, AD Jamieson, DM Bailey, EJV Battle, C Henriques and KM Kemp

 

Excess pore pressures induced by installation of suction caissons in NC clays

J Cao, R Phillips, R Popescu, JME Audibert, Z Al–Khafaji

 

Laser stripe imaging to determine three–dimensional information on fish shoals

S Tetlow, S Creaven, EG Jones and DG Reid

 

Mapping seabed biotopes using sidescan sonar in regions of heterogeneous substrata: Case study east of the Isle of Wight, English Channel

CJ Brown, AJ Hewer, WJ Meadows, DS Limpenny, KM Cooper and HL Rees

 

Interfaces between the submarine cable industry and other seabed users around UK coastal waters

N Irvine and R Borwick

 

Technical diving

M Caney

Book Review:

The Sea’s Enthrall: Memoirs of an Oceanographer, by Dr Timothy Parsons

Reviewed by M Angel

 

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Underwater Technology Vol 26 No 2

Summer 2005

A Personal View

Marine Renewables — Will the UK drop the ball (again)?

P Wolfe

Technical Papers

Trends in scientific diving: an analysis of scientific diving operation records, 1970–2004

MDJ Sayer and J Barrington

 

Closed loop identification of a remotely operated flight vehicle

M Wang and R Sutton

Technical Briefings

The use of renewable energy systems in coastal defence

JW Griffiths, DE Lennard R Kirby, T Thorpe

 

Seabed coring in the ice–covered waters of the Arctic Ocean for the Integrated Ocean Drilling Program

D Evans and A Skinner

Meeting Reports

Current status of marine minerals

David Cronan

 

The 6th Renewable Energy Finance Forum (REFF) and marine renewables

Don Lennard

Book Reviews

Dive, Dive, Dive — Submarines at war, by Michael Gunton

Reviewed by DR Wardle

 

Raising the Kursk, by Hans Offringa

Reviewed by Roger Chapman

 

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Underwater Technology Vol 26 No 3

Winter 2005

A Personal View

The role of Subsea UK

DL Pridden

Letter

Second letter from Madras: Progress in the Bay of Bengal Large Marine Ecosystem (BOBLME) Programme

P Verlaan

Review

A review of the uses of work–class ROVs for the benefits of science: Lessons learned from the SERPENT project

IR Hudson, DOB Jones and BD Wigham

Abstract: This paper reviews the contributions of underwater science in continuing to develop new technology to explore the marine environment and how collaborations taking place between the oil and gas industry and science are facilitating this process. A case study focuses on some of the results and highlights from the SERPENT Project. SERPENT (Scientific and Environmental ROV Partnership using Existing Industrial Technology) is a collaboration programme that was designed to make better use of remotely operated vehicle (ROV) technology and data available through links with marine operations in the oil and gas industry. Oil and gas exploration and production activities in the marine environment are increasing. The amount of global hydrocarbon reserves removed from below the seafloor is set to increase over the next 5–10 years with exploration heading into deeper, more remote waters, many of which have yet to be fully explored. The only way that these remote areas may be documented is through a working relationship with industry, with mutual benefit for both sides, and learning from technology that is already in place for the benefit of science.

Technical Papers

Research on the pressure compensation for the underwater hydraulic motor

YM Li and QF Wang

Abstract: Considering the influence of underwater ambient pressure (UAP) on underwater hydraulic motors (UHM), and utilising the state–of–the–art of pressure compensation of underwater hydraulic systems (UHS), this paper proposes a pressure compensation technique for the UHS where the hydraulic power unit is installed inside a deep diving submersible or a submersible drilling platform with atmospheric pressure, some actuators of which are directly surrounded by seawater and others are installed inside it. An underwater ambient–pressure–compensation valve (UAPCV) has been developed. The pressure in the return line of the external sub–circuits of the UHS is compensated by this UAPCV, but not that of the internal sub–circuits. Theoretical analysis, simulation and experimental results show that reliable pressure compensation can be ensured with a small flow–rate by the UAPCV. The operational performance of the UHM is further improved after its leakage pressure and return pressure are compensated.

 

Estimation of underwater noise – a simplified method

RA Hazelwood and J Connelly

Abstract: A set of procedures has been developed to allow preliminary estimates to be made of underwater noise and its effects on marine species. They do not require detailed acoustic survey data, either of the site or of the proposed plant. However, they still facilitate the comparison of different project proposals to assist in the optimisation of equipment layout and routing. Noise may be due to specific sources, such as ships and marine equipment, or assessed as a general background level. Some aspects of acoustic analysis applicable to more detailed environmental impact assessments are also described, particularly relevant when comparing noise spectra with audiometry data appropriate to different species of wildlife.

 

The use of fault tree analysis to visualise the importance of human factors for safe diving with closed–circuit rebreathers (CCR)

S Tetlow and S Jenkins

Abstract: Closed–circuit rebreathers (CCR) have been used for many years in military diving but have only recently been adopted by technical leisure divers, media and scientific divers. Rebreather divers appreciate the value of training, pre–dive checks and equipment maintenance, but it is often difficult to visualise just how important these factors are and how they inter–relate for a rebreather. In this paper, the well–known technique of fault tree analysis (FTA) is used to identify risk in a rebreather. Due to space constraints, only the branch of the tree for unconsciousness as a result of hyperoxia is considered in detail but, in common with the whole tree, end events are shown to be human–factor related. The importance of training to the emergency situation, the use of formal pre–dive checklists and the value of good design to prevent accident escalation are discussed further.

 

Results of cylinder detection and fitting from real three–dimensional underwater acoustic images

RC Patel and AR Greig

Abstract: For remotely operated underwater vehicles operating in the vicinity of offshore platforms, the object recognition and detection of cylinders is of importance because many platforms are constructed from connected tubular elements. This paper briefly reviews acoustic cameras and then presents a cylinder–based model matching procedure for 3D underwater acoustic camera images. Cylinder identification is achieved using a combination of information from the 3D acoustic image and the 2D intensity map. The paper concludes with some sample results of images of a scaled oilrig structure captured using a 3D acoustic camera.

Book Reviews

Oceans 2020: Science, Trends, and the Challenge of Sustainability

Reviewed by T Guymer

 

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Underwater Technology Vol 26 No 4

Summer/Autumn 2006

A Personal View

Supporting new waves in marine technology

L Slade

Technical Papers

Transient free–surface waves due to impulsive motion of a submerged source

J–J Shu

Abstract: The problem of a viscous flow past a submerged source starting from rest and moving with a constant velocity, below and parallel to a free surface, is examined and asymptotic expressions for long–time evolution of free–surface elevation are obtained. The results show explicitly the viscous effect on the free–surface elevation and no surface tension effect on the asymptotic wave.

 

Extracting the cultural heritage: new challenges for the underwater archaeologist

G Momber

Abstract: Analysis of archaeological sites stratified within marine sediments can open a window to cultures that are now lost between the waves. These sites and their environmental context harbour a resource that can also provide index points for sea level rise during a period of acute climate change. A decade of archaeological investigations in the western Solent by the Hampshire and Wight Trust for Maritime Archaeology, utilising divers and geophysical survey data, has led to the discovery of Mesolithic sites within submerged landscapes. They lie between 6.5m and 11.5m below British Ordnance Datum. However, the discovery of these delicate and vulnerable sites is presenting new challenges to the maritime archaeologist. The need to record, rescue and interpret the remains underwater sampling techniques.

Technical Briefing

Sea bass (Dicentarchus Labrax) and a sea change for 21st century fisheries

J Hind

Meeting Reports

Selected Summary Highlights from the 53rd Meeting of the intergovernmental Marine Environment Protection Committee (MEPC 53) of the International Maritime Organization (IMO), 18–22 July 2005

P Verlaan

 

Selected Summary Highlights from the 27th Consultative Meeting (LC 27) of Contracting Parties to the Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972 (London Convention 1972) held at IMO Headquarters, 24–28 October 2005

P Verlaan

Book Review

Diving and Subaquatic Medicine, by Carl Edmonds et al

Reviewed by J Bevan