To study the organisms of the deep-sea benthic boundary (which of course is well beyond the present range of deep-sea divers), the biologist requires a platform from which to deploy the special sampling gear or experimental apparatus needed to examine, observe or experiment with the biota. This platform can take two forms: a specialized oceanographic research vessel, or a research submersible, usually operated from a research vessel doubling as ‘mother’ ship.

Usually such vessels are engaged in voyages, or ‘cruises’, lasting from a few days to several months. Preparations for a deep-sea cruise have to be very thorough as the sites to be sampled are often remote from land. Although the logistics of such an undertaking are complex, involving all aspects of ship management, the scientist in charge of the cruise is responsible for identifying the equipment necessary for sampling as well as the equipment required for onboard laboratory analysis. The different categories of bottom-dwelling deep-ocean fauna (summarized at the beginning of Part II) naturally present differing problems when trying to collect samples, or in deploying other apparatus, for studying them. Furthermore, it will be necessary to accurately estimate bottom depth and positional coordinates of the ship, and for any overside gear in relation to it; while data on the nature of the bottom and the structure and dynamics of the overlying water column will also assist a successful programme.