One of the key issues dealt with is the potential for contractual disputes in situations where survey and DP users are from different companies and where installation, manipulation or reconfiguration of a resident shipborne positioning system for either survey or DP operations may affect its performance for the other party. Compiled as a result of discussions between IMCA's Offshore Survey & Marine Divisions, the guidelines emphasise the need for careful forward planning and cooperation in the interests of safety as well as operational effectiveness. They conclude with a set of detailed recommendations for those considering sharing global navigation satellite systems such as DGPS and the differential version of its Russian counterpart, Glonass.

Printed copies of the guidelines - IMCA S 009 - are available from IMCA at £10 for members and £25 for non-members at 5 Lower Belgrave Street, London SW1W 0NR (Tel: 020 7824 5520 Fax: 020 7824 5521 Email: publications@imca-int. com).