Scripps Institution of Oceanography

A workshop on stable oceanographic research platforms was held at the Marine Physical Laboratory June 29-30, 1987. Research needs of several scientific disciplines, including physical oceanography, air-sea interaction, biological oceanography (especially bio-optics), and acoustics were discussed in detail with respect to the advantages of various stable platforms.

This workshop was stimulated by recent requests involving the use of FLIP in weather conditions beyond its original capabilities, with more equipment and people than it can hold, and by the naval architect's opinion that FLIP, after 25 years of service, may be approaching the need for some expensive structural rework. While the immediate purpose was to consider requirements for a new FLIP, the workshop adopted a much broader approach recognizing the unique advantages of different stable platforms for particular research needs.

The physical oceanography, bio-optics, and acoustics communities, from their experience working with FLIP, cited very specific reasons for a new FLIP with increased capabilities for rough weather operation (100 foot wave survivability, 60-80 foot wave operations), improved laboratory, living and working spaces and increased power capability. It should continue to retain deep water mooring capability, and to present a minimal cross-sectional area both in air and water.

SWATH ships and submarines, stable platforms with mobility, were also discussed. In addition to their ability to provide improved work platforms for a variety of oceanographic experiments in higher sea states, small high-speed SWATH ships could increase dramatically the sampling region about a moored or drifting stable platform. Small submersibles, manned or autonomous, could also be launched and recovered from a large platform using present technology. For expeditious gathering of data under the Arctic ice pack, a manned research submarine is virtually the only means by which this area can be studied.

The payload capability of a flippable barge or a larger FLIP could make possible all-weather operations possible with either autonomous or manned submersibles, by providing them with a deep underwater garage for launch and recovery. A track system for bringing the vehicle through the surface to a station for crew rotation and resupply would eliminate the dangers from rough seas associated with present operations.

The acoustics community also was interested in the capabilities of a large semi- submersible from the standpoint of handling very large and powerful sound sources as well as for deploying multiple acoustic arrays for three dimensional measurements of the ambient noise field.

The biological community also was interested in a large platform such as a semi- submersible which would he suitable for time-series studies and which would have resupply capability at sea for logistics as well as personnel rotation. Typically, large rigs can pick up 300 ton packages from resupply vessels. Such large lift capabilities also enhance the utility of a large platform to launch and recover highly mobile vehicles to capture and return for analysis samples with minimum delay time, a key unique feature of an Iron Island station for biologists along with the stability necessary for high accuracy laboratory work at sea. Similarly, a moored rig would make possible long term benthic studies including sampling by remote underwater manipulator (RUM) type vehicles which have already been used by the biological community in deployments from the Research Platform ORB. Results of an NSF funded study on the need for long time-series measurement studies, while not presented at the workshop, are included since they complement and reinforce our conclusions.

The scale of operations for large platforms, especially semi-submersibles, becomes similar to that of the Deep Sea Drilling Project, requiring steady use by a large base of scientists that may require an international effort in order to be economically feasible.

The unexpected, rather broad, pluralistic approach this workshop adopted in considering requirements of the research community for stable ocean platforms made the proceedings both more interesting and complex. A wide variety of platform types was considered, all of which already exist in some form. Each had unique contributions for satisfying the particular requirements of various research communities for stable ocean platforms. It may be, as we focus on the realities of operations and needs, that hybrid combinations of existing platforms will evolve as candidates for future use. Just as the original FLIP was designed as a simple platform for a particular acoustics experiment but with other potential users in mind, its evolution as a platform useful to other interests may serve as a model for the development of future larger stable platforms.

Twenty-five years of operations have demonstrated the value of RIP FLIP as a platform for collecting time-series data on physical characteristics of the ocean. Twelve years of operations of SSP KAIMALINO have demonstrated the value of the SWATH ship as a mobile platform for research and development in demanding sea conditions. Floating stable platforms offer the possibility of measurements in higher sea states and wider latitude variations, of "sea truth" measurements for observations from space, and for coordinated multi- disciplinary time-series measurements of oceanic ecosystems.