Development of an Unmanned Cable Controlled Submersible Vehicle for Surveying and Sampling Exposed Subsea Rock Shelves
Authors: Skidmore Gordon , Bircham John 
Published: October 2008

In geological survey work on the U.K. Continental Shelf, the Institute of Geological Sciences found a need for new equipment to extend their operating capability beyond that of the conventional diver.

To meet this requirement British Aircraft Corporation have developed and built an Unmanned Cable Controlled Submersible (CONSUB) which has recently completed a successful series of sea trials.

During these trials which took place around the Northern coast of the U.K. and in Norwegian waters, CONSUB successfully carried out photographic and video survey work together with retrieval of geological rock core samples.

1. INTRODUCTION

The following paper describes the design, build and testing of an elementary unmanned mobile platform. It can be manoeuvred over selected areas of the sea bed at depths down to 600m by means of power and signals passed down a buoyed umbilical cable which connects the vehicle with the mother ship on the surface. Information on the location and attitude of the vehicle is transmitted from a television camera on the vehicle through a closed circuit to the vehicle operator on board the ship who can make manual adjustments as required to close the loop.

The system was commissioned by the Institute of Geological Sciences, (LG'.S.) in order' that scientific personnel might make visual observation of the sea bed through a closed circuit television system.

Video and photographic records of the areas studied could be made for detailed analysis at a later date and rock core samples (1cm diameter by 5cm long) can be recovered from the sea bed by deploying a small rock drill.

The project was jointly funded by the Department of Trade and Industry and the Institute to encourage the development of such vehicles in this country. Further funding was provided by the BAC as an investment in underwater technology. The Department also made available scientific and technical advice from the Marine Technology Support Unit at the Industrial Division of the Atomic Energy Research Establishment at Harwell.

2. THE REQUIREMENT

Surface conditions around the UK coasts are such that there are many days when the sea is too rough to deploy the conventional over theside drill. In order to minimise downtime for sampling and extend the range of operations beyond the conventional diver's limits, the IGS' plan to operate the cable controlled vehicle and to continue to make, observations and rock core recovery until it becomes impracticable for the ship to remain on station. In addition, they wish to be able to deploy the system from a variety of more specialised support ships. This background then led to the following.A very simple basic vehicle which would be controlled manually from the surface and which would be navigated visually.The depth capability initially of 200m and an early increase to 600m.The capability of operating in a current of lm/s at a minimum forward speed of 0.15 m/s over an area of at least 45m radius.A pan and tilt head on which would be mounted a television camera, a pair of steroscopic film cameras, flood and flash lighting, and a small rock coring drill.