This paper addresses both the aims and the practicalities of offshore site investigation from the perspective of a client representative and that of the end user, be that a client, a geotechnical designer or a verifying authority. In particular, it seeks to share a few of the lessons learnt from over 30 years of experience in these various roles.


The themes of this conference are ‘confronting new challenges and sharing knowledge’. In line with the latter of these objectives, the paper seeks to share some of the personal experience gained during offshore geotechnical site investigation for piled, gravity and suction-installed foundations, jack-up rigs, pipeline and anchors.

It outlines the role of the client representative, addresses the requirements of the end users of the geotechnical data obtained and discusses how best to achieve those goals.

The paper is not intended to be manual for client representatives, nor does it set out to criticize the way in which any particular site investigation contractor performs its tasks. It does, however, contain some thoughts and recommendations on the role of the representative based on the author's experience, as well as give some insights into how the end users can be better served without impacting too much, if at all, on the duration of the site investigation, profit margins of the contactor or cost to the client.

All opinions expressed herein are the personal views of the author. References to ‘he’ are for convenience only.

The Role of the Client Representative

The role of the client representative, during an offshore geotechnical site investigation, can briefly summarised as ensuring, as far as possible, that high quality, useful soils data are acquired, within budget and without harm to personnel or the environment.

An ideal representative should have a thorough understanding of how the data are subsequently to be used. He should be prepared, qualified and empowered to make appropriate onsite decisions on day-to-day matters and minor changes in scope, and to make recommendations to the client about major changes in order to obtain maximum, cost-effective information from the investigation. He should be fully aware of commercial considerations and, most importantly, make sure that particular attention is paid to the safety of personnel and the impact of the work on the environment and the community. A representative with these qualities will help the client achieve value for money while promoring safe working practices.

On many projects, a single client representative will have to cover all aspects of the job, including geotechnical, positioning, contractual, logistical and safety issues, over a full 24hr offshore working day. To do the job properly requires the ability to make on-the-spot, yet well thought-out, decisions during day or night. Keeping the vessel on standby, pending a decision from onshore, should be avoided if possible. However, the representative must also limit the hours he works for his own safety, notwithstanding any statutory obligations, while nevertheless being prepared to be called at any time.

Usually, the client representative will be best able to take an overview of the investigation

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