When we take our rock coring drills (BGS Rockdrill/Vibrocorer), (BGS Oriented/Bridge Drill) to sea it has become increasingly the norm to have some form of site selection picture available to the geologist once the equipment has made its landing.

To this end we have evolved a number of methods to facilitate this, depending on the drill and cable type. Initially the video started being devised for the Bridge drill which was being run from a single armoured coaxial cable. This resulted in the most complex and cumbersome method with a relatively slow update rate. This system, christened FSK, had the major advantage in that it allowed video or data to be transmitted up or down at the same time as 1500Vac power (up to 3kW) was being sent down to the sea bed. During our investigations into how to improve the frame rate from the appalling 90 seconds, we came up with two significant improvements.

The next idea, which we never actually used in anger, was the Vitalpoint System. This promised to allow us to send video at two or better frames a second up a dedicated twisted pair. In practice this proved to be a very usable system, unfortunately it was overtaken by circumstance as we jumped direct from single coax for all data and power to a pupose built cable containing optic fibre. Using a purpose built board available from Focal Technologies we purchased the ability to send up three video channels as well as give us multiple bi-directional data streams, allowing controls and data to travel to and from the drills, simultaneously giving us realtime video(s) from the sea bed. Not all cables have optical-fibre so the Vitalpoint stuff might well come in useful later. It will certainly give a back up system to the fibre in the older cable, using the multiple screened twisted pairs available.

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