Development of CTD-systems

The British Trail


Terry Sloane

NBA (Controls) Ltd was formed by Nicholas Brian Anscombe in the Mid 1960’s in Farnborough, Hampshire, UK. ,  along with two others, John Partridge and Mike Borrow.  The three of them shared some space behind the Snow white laundry in Farnborough and beavered away on their own projects.  Nick went on to form NBA, and made current meters mainly and temperature meters, John Partridge played around with acoustic diver location systems and formed Sonardyne and Mike, with his partner Mike Humphrey invented the JIM diving suit and formed UMEL (Underwater Marine Equipment Ltd). Mike later sold out to Oceaneering.  So, only Sonardyne has stayed the course, but several of the current batch of UK companies can trace their roots back to these three pioneers.


In 1977 Terry Sloane joined NBA as a junior design engineer. In about 1987 Nick could no longer support the company and NBA was sold to MERTEC.  They changed the name to NBA Environmental Systems. By this time Terry Sloane became Technical Director of NBA Environmental Systems, developing the own inductive conductivity cell: “The first inductive conductivity cell would have been designed in about 1984, and was a solid potted device which suffered from all sorts of instability and was susceptible to pressure effects.  Between then and 1989  we developed the inductive conductivity sensor in its own pressure case, and with the complex feedback compensation system


Assembly consisted of a plastic-coated aluminum alloy case that housed the transducers and electronics. The transducers are all mounted around the bottom cap and protected from damage by the surrounding guard. The output unit was housed in a portable, rugged, polycarbonate case, complete with a transparent lid. All underwater sensor units and surface control units were interchangeable, allowing the user system flexibility.

In 1997 Terry Sloane transferred the rights to manufacture his inductive cell to the Canadian company Richard Brancker Research Ltd.


Charles Quartley

Another British company Valeport Ltd. was founded near Dartmouth, in Devon in 1969 by Jim Stevens and originally sold the Braystoke Flow Meter, an impeller-type device which was used in the feasibility study for the Thames Barrier . The popularity of this led to an expansion of the company into other types of flow meters and accessories. Valeport was then purchased in 1982 by Oceonics Group PLC prior to their flotation, which led to an expansion of Valeport’s expertise to include CTD measurement. Oceonics sold Valeport in 1985 in a management buyout to the chairman Charles Quartley. The business remains solely owned by the Quartleys family.

In 1975 the company develops the STM 500, the salinity and temperature meter.

Valeport CTD600 MarkIII

The Model 600 MKIII is the third generation of the successful Valeport 600 series CTDs using proven industrial standard sensors and has been developed to meet the needs of oceanographers, hydrographers and surveyors who require an accurate CTD with the flexibility of configuration and large memory capacity, which can output directly to a PC and can be used in both direct reading (600DR) and self-recording (600SF) mode. The instrument had 3 data communication methods built-in which offer great flexibility for configuration and use with a wide number of cable types and lengths. Calibrations of all sensors is held within the instrument and data is provided in engineering units. Power may be taken from the own batteries or from the surface battery or the surface unit if connected. The unit had standard memory 128 kbyte, which could be extended to 1 Mbyte.

Specifications of Valeport 600CTD MarkIII