Where appropriate data does not already exist, the delineation of the outer limit of the continental shelf as defined by the Article 76 UNCLOS guidelines requires a considerable acquisition effort in terms of both bathymetric and geophysical data. "State-of-the-Art" programmes designed to acquire these data are inevitably expensive and can potentially place an inordinate drain on coastal state's budgets.

In view of the UNCLOS requirement for nations to support their claims for continental shelf limits beyond 200nm of baseline within ten years of ratification, there exists an urgent need to find a cheap and acceptable method of obtaining and compiling the required data.

This paper examines a range of medium and low-cost options appropriate to coastal states with limited resources, but which maintain a level of required accuracy. Cost-efficiency measures explored include the use of "ships of opportunity", collaborative but targeted surveying ventures. The benefits and disadvantages in the use of readily available and relatively cheap survey equipment (such as focused, single beam echo sounders and single channel seismic profilers) are discussed.

We present an assessment of the generic survey systems, which could be employed to support claims on continental shelf resource management. We argue that far from accepting that the topographic and geological mapping of the coastal state's waters should be completed by the latest generation of data acquisition systems, a more cost-effective and appropriately budgeted programme can, in most instances, be established.

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