Ship Squat and Interaction (eBook)

Published Date

September 2009

Also available in other formats:

Ship Squat and Interaction (eBook)

(Excludes any applicable taxes)

Ship squat and interaction are major concerns for the handling of ships, particularly in shallow waters. This book aims to give a more thorough understanding of these conditions, using worked examples, case studies and the author’s personal computations and time-proven formulae.

The phenomena of both Ship Squat and interaction are a major concern for the handling of ships, particularly when ships are operating in shallow waters. Ship Squat can be defined as ‘the decrease in underkeel clearance as a ship moves forward after being static’, this book aims to give a more thorough understanding of these conditions, based on the authors work in this particular area since completing his PhD on the subject in the early 1970s.

After decades advising operators, pilots and port authorities on this subject matter, professionals in these positions or Shipowners & Operators, Mates, Masters, Tug Operators, Educational Establishments, Ship-model Tank staff, Ship Simulator staff and Maritime Examiners will find this book to be of great use.

A great commentator on these subjects over the years in the maritime press, this book brings together the work of Dr Barrass in a single publication and is a comprehensive work on this interesting subject that is often not well understood in the marine industry.

Dr Bryan Barrass has worked in the shipping industry since 1953, resulting in over 50 years of industrial, lecturing and research experience to date.

He commenced as a Ship Draughtsman, working for 11 years at the Swan Hunter shipyard in Wallsend. In 1963, he became a Lecturer in Naval Architecture in Sunderland. From 1967 to 1993, he worked at Liverpool John Moores University, lecturing to Maritime Degree students, Masters, Mates and Marine Engineers.

In 1993, he retired from full-time work. He became a visiting Lecturer and authored six books on ship stability, ship squat, ship design and ship performance. His interest in ship squat began in April 1972, starting on research for his PhD degree. He has lectured part-time at six UK universities, as well as in Singapore and Australia.

Dr Barrass has supplied information on squat worldwide to shipowners, academia, maritime institutions and consultants, and maritime journals. He has also worked with many Port Authorities, including the Port of London Authority, Milford Haven PA, Liverpool PA, Humberside PA, Tyne PA, Truno PA, Newhaven PA, Bordeaux PA, Klaipeda PA, Nantes PA and Hamburg PA.

Title: Ship Squat and Interaction (eBook)
Number of Pages: 182
Product Code: WS1062EA
ISBN: ISBN 13: 978-1-905331-60-4 (9781905331604), ISBN 10: 1-905331-60-6 (1905331606)
Published Date: September 2009
Author: Bryan Barrass

Customer Reviews

Ship Squat and Interaction Review by Captain Hugh N. McQuaid. MRIN. MIQA. Director. Marcon Associates Limited
The advent of smaller bridge management teams, yet again highlights the need for the advanced passage planning requirements to give detailed analysis of the arrival tidal conditions, linked in with prevailing weather conditions that may or may not influence berthing ranges at the next port. These calculations must be seriously reviewed by both the Ship Master, Ship Owner, Port Managers and Pilots to ensure safe passages of vessels using their ports. This also has an impact on other vessels movements, that by draught constraint, are required to sail or arrive at the same time, again increasing the need for risk analysis on the effects that squat and inter-ship interaction can cause, especially in canals and narrow channels. I would also recommend the book to Large Yacht Masters as well as Brokers and Management Company’s. These vessels are increasing in size year on year, yet Owners still wish to visit the most popular destinations. The increase in size is a correlation between draught and speed, while in the majority of cases the Yacht Masters do their own pilotage. Therefore, the need for more diligence is required for a more professional understanding of the subject. I particularly like the individual highlighted icons on selected pages that readily bring the readers eye to the important sections on that page.The mass of mathematical formulae for the academics is giving all readers a more detailed understanding of the theories behind the numerous calculations to be found in this book.

Dr Barrass, has again provided the professional mariner and port operator, with a valuable tool to enhance their understanding and appreciation of this extremely important aspect of the mariners professional and operational expertise.
(Posted on 01/03/2010)
Ship Squat and Interaction Review by Nautilus Telegraph Review
Regular Telegraph readers probably need little introduction to the problems posed by ship squat: it’s a subject that has featured all-too regularly in accident reports, and has prompted contributions to the paper by Dr Bryan Barrss, one of the world’s leading experts on the subject. Now Dr Barrass – a former naval architect and university lecturer – has produced a 180-page book that addresses both ship squat and interaction, seeking to give everyone in the shipping industry a better understanding of the dangers that they can present. With the aid of excellent graphics, the book demonstrates why squat has become an increasingly important issue within shipping safety. The big increase in average ship sizes and speeds, coupled with poor dredging in many areas, has led to dramatic decreases in static underkeel clearances – with Dr Barrass referring to more than 110 groundings that resulted from excessive squat. Using case studies and worked examples throughout, the book examines the factors that influence squat and interaction – including speed, and water depth and width, as well as ship-to-ship and bank effect. It also sets out squat curves and formulae to assist owners, operates, officers and pilots in safe passage planning and gives advice on using spreadsheets to determine squat together with guidance on reducing the impact of interaction in such scenarios as river and canal passages replenishment at sea and drydocking. Dr Barrass completed his PhD on the subject in the early 1970s, and this clear and comprehensive book will surely serve as the definitive publication for the industry piece by Bob Wilson, who wrote the Telegraph’s popular Ships of the Past feature for the best part of a decade – and many other well-known figures have contributed, including the marine artist Geoff Hunt. The book opens with an interview with the director of the National Maritime Museum, in which he discusses the plans for the museum’s model collection. At £30, the book isn’t cheap, but it is very well presented, with high quality paper, hardback binding and glossy photographs, and it is a publication that enthusiasts will want to keep for future reference. (Posted on 01/10/2009)

Bought this product? Why not review it?

If you have a question about this product, please contact us directly.

Windows eBooks:


To access the eBook, you need to install our free Windows eBook Reader.

The application can be downloaded from:


Standalone eBooks are supplied with 1 licence + 1 backup and are not transferable between platforms.


Remote Desktop Services (Terminal Services) and virtual environments are not supported.


The Windows eBook Reader works with Windows XP or later OS (but not Windows RT).

See more details.


Cloud (online) eBooks:


The Cloud (online) eBooks use Microsoft Silverlight browser plugin to deliver the best possible reading experience with the ability to work in offline mode.


It is an annual subscription service (i.e. each eBook is purchased for 1 year of use).

Online licences are not transferrable to Windows or iPad (or vice-versa).


Silverlight is compatible with the major web browsers used on Windows and Mac OS X operating systems.

However it is not supported on Linux, Android, Windows RT and iPad devices and therefore the Cloud eBooks use an HTML site in these instances.

The HTML site is more restricted than the Silverlight version.


See and more details.


Note for Mac Users:


Mac users can read Windows eBooks with Boot Camp or using virtual machines such as Parallels Desktop, Virtual Box, ...

Alternatively, Cloud (online) eBooks are accessible on Mac, including the Silverlight plugin with offline mode.


Note for Linux Users:


Linux users can read Windows eBooks using a virtual PC.

Alternatively, the HTML version of the Cloud (online) eBooks is accessible.


Note for Tablet Users:


Tablets owners can use the HTML version of the Cloud (online) eBooks.