The recent trend toward Diverless intervention in the Offshore Industry has resulted In the development of remotely operated variants of a number of basic Items of equipment.
TRONIC LTD In co-operation with SUB SEA OFFSHORE are currently engaged In the manufacture and test of an ROV Mateable connector based on existing technology where possible.
The significant criteria addressed during the programme include tolerance to misalignments In various planes, rough handling, ease of assembly, and repeatable electrical properties to name but a few.
The project is seen by the participants as on-going and a number of improvements have already been identified as being desirable In the flush product.
This paper is intended to provide an overview of the progress to date In the development of an ROV mateable connector. The programme is still In its early stages and, whilst significant features have still to be proven by long-term testing, recent tests have established the basic soundness of the design. The project began In December 1990 following initial discussions with Sub-sea Offshore. Whilst the basic requirement for diverless systems has been long established and was the stimulus behind the replacement of manned submersibles with ROVs In the late 1970's, it is only within the past 5 years that the design of conductive couplers has progressed to a stage where sub-sea mating is achievable with consistency.
Whilst sub-sea mateable connectors existed prior to 5 years ago, In general they were unable to provide respectable and repeatable results or lacked the considerable robustness required to withstand handling by ROV. Additionally, none of the existing connectors were designed with 20 year+ immersion In mind, being either Neoprene moulded or constructed from unsuitable materials.
The design, therefore, needed to bring together the features of several basic connector types, and to Introduce the robustness and tolerance to mis-handling inevitable with remote connection.
In addition to the improvements achieved In connector design, certain other parallel developments had to take place to allow the requirement to be addressed. The most significant of these is the establishment of versatile handling systems, manipulators, tools etc, to allow the precise connection and disconnection of couplers (both hydraulic and electrical). Also of great importance to the project is the development by various ROV manufacturers of docking systems which can reduce the necessary dexterity of manipulation and increase the mating force available.
Two separate approaches to remote connection are to be considered:
Provision of ‘Stab Plates’ to enable connection to be made concurrent with equipment installation subsea.
Provision of fixed connectors on one half of the structure with the mating being carried out by ROV following installation of the remainder of the equipment
Whilst both systems have their merits and limitations, it was considered that, notwithstanding the necessity for ‘Stab Plates’, it was the ROV mateable connector that provided the most versatility.
The perceived limitation of the ‘Stab Plate’ system is that, as it forms part of the structure being assembled, without careful design the coupling can be subject to high, non axial, mating forces and approach rates.
