Navigation In Focus Bino Compass miniature long-range bearing compass. Made by Offshore Instruments Ltd, 28 Blythe Road, London W1 4. Designed by Michael Dupree, Des RCA MSIA. Approximate retail price: £24.50 ex VAT.

Bino Compass is the trade name for a unique product made by Offshore Instruments Limited. It is a miniature long-range bearing compass, made in matt black plastics, which is used in conjunction with 40mm or 50mm marine binoculars to increase the accuracy of bearings taken at sea when the naked eye becomes unreliable. It was introduced in this country at the Earls Court Boat Show in January last year. The original idea for this instrument came from Robby Brann, an experienced yachtsman and managing director of Offshore Instruments. His firm began its activities in 196S by importing a special compass from France, which operated on a new optical principle which was later developed in the Bino Compass. The advantage of it was that both the compass scale and the distant landmark on which the bearing might be taken would be in focus simultaneously. When using an ordinary hand-bearing compass, the yachtsman must focus his sight first on the landmark and separately on the compass scale. The possibility of parallax error is great. With the Bino Compass' Offshore Instruments and designer Michael Dupree have extended the principle to deal with difficult bearings over long distances or in poor visibility. When the Bino Compass is slotted into its collar on a pair of binoculars, a large scale is seen superimposed on the enlarged view of the object, so that a buoy or lighthouse can be identified and its bearing logged to the nearest degree in situations where normally this would be impossible. In daylight the compass is illuminated by natural light, but in dusk or darkness a l 5v printed circuit provides a choice of bright or dim light projected through a 90° prism onto the compass card.

The Bino Compass itself weighs 31/2oz and is supplied with a small viewer (for use with the instrument when used separately from the binoculars) and an adjustable collar strongly moulded in glass reinforced noryl. In his designs for the moulding tools, Michael Dupree has made possible a very high level of precision in the assembly process at an assembly cost considerably lower than is normally associated with an instrument of this complexity. The detailed technical development was carried out by director Rodney Hogg, in consultation with Professor Walter Telford of Imperial College London.

Design Journal, No.304, Contract and Consumer Goods, April 1974. pp.35-41.