• Decca Radar Ltd., Decca House, Albert Embankment, London, S.E. 1, have been privileged to provide radar for the R.N.L.I, for eight years.

The Decca 202 series and Kelvin Hughes Type 17 were the first sets to meet all the Institution's strict operational requirements.

Transistorisation brought great benefits, not to mention reliability. The display is a little smaller but the main space gain is with the transceiver and inverter. Valve-type transceivers were like small trunks where transistorised ones are attache cases and instead of a sizeable electric generator one has, in the case of the D202, an inverter measuring 17 in. x 16 in.

x 8 in. A glance in the cockpit of a life-boat would convince anyone that there was only room for the earlier types at the cost of other equipment. Power consumption was reduced from about 1,000 watts to 310 (360 in a gale), a very important point in a life-boat with so many calls on the available supply.An unrelated but parallel development was the lightweight slotted waveguide scanner which did not appear until the late 1950s, the earlier configurations being much heavier.

The biggest general benefit conferred by transistorisation was enhanced reliability (saving of power and space not being so important in larger vessels) and this is, of course, where the two radars concerned really score with the R.N.L.I. Careful records are kept at Decca of every single radar installation extant (there are some 35,000 now at sea out of 41,000 sold), every service visit or ship's report being documented.

These are normally within three weeks of being up-to-date and, • of course, a vast amount of feed-back information is afforded to designers and service personnel.

The advent of transistorisation caused an immediate and drastic leap in standards of reliability (now only being improved upon by the latest solid-state technique) and it is true to say that with valve equipment it might not have been worth fitting radar in the testing conditions of a life-boat, certainly not in the smaller ones.

Nineteen life-boats are equipped with the D202. D202 has been called 'the work-horse of the radar world", having put up what is considered a record of 7,900 sales to date. Here it may be mentioned that Decca is proud of the fact that the very first D202 ever, was installed on and is still giving good service with the R.N.L.I.'s life-boat The Earl and Countess Howe, a 48-foot 6-inch Oakley, based at Yarmouth, Isle ofWight.

The Decca 101 (and Super 101) is smaller still and used in nine life-boats. It has a maximum range of 18 miles instead of 24 but this is not usually much handicap since radar sees almost directly, as the human eye, and the low vantage point of a life-boat limits maximum range in any case. The Decca 101 has its transceiver aloft with the scanner, saving further wheelhouse space, and an even more compact display, though the actual picture is about the same. The Decca records say that this radar is the most reliable ever produced by the company, which is mainly on account of its simplicity. The 101 is approaching the D202's figure, with sales of 7,300, about equally distributed between work boats and pleasure craft.

Some 12,000 Decca D202's and 101's are at sea in tough commercial circumstances, boththese rugged little radars finding particular favour in the tough conditions on the north-east Scottish coast where, fishermen expect a lot and are not always the gentlest of operators.

Decca applies the AGREE (American Government Advisory Group on the Reliability of Electronic Equipment) procedure to all its radars. This was originally laid down for the testing of military and aerospace equipment, which would have unacceptably expensive results if it failed. The prolonged environmental tests (in, for instance, extremes of heat, cold, humidity, and of vibration dynamic deceleration), are carried out on batches of equipment under development. Similar prolonged tests are also carried out on bought-in components.

Lastly, tests are made (as a sort of 'long-stop' to quality control inspection), on large random batches of final equipment subsequently taken from the production line and put on the rack just to ensure that no production process has lowered standards. A chance visit to the AGREEchamber will reveal an average of ten radars being cooked (or frozen) at any one time.

Many seemingly bright ideas, new materials with apparent advantages, less expensive components and other apparently attractive innovations never get to the prototype stage let alone into production, because they have been found wanting, and it is only when all the AGREE tests have been successfully passed that a new radar goes on the market.

• A 40 ft. Keith Nelson hull fitted out as a high speed rescue launch for the Dutch life-boat service (Koninklijke Noord-en Zuid-Hollandsche Redding-Maatschappij), was completed at the Vosper Thorneycroft Group's Portchester, Hampshire, shipyard in 1969. With a top speed of 28 knots she is claimed to be the fastest life-boat of her kind in Europe, (picture page 155).

The new vessel is based on a standard Keith Nelson design of 40 ft. glass reinforced plastics hull, similar to one built in 1968 for the R.N.L.I.

which was, however, powered for a top speed of 18 knots.

The Dutch boat's main task is rescue, primarily offshore in all but the worst weather.

A vessel of this type, is particularly useful for searching a large area in conditions of poor visibility when seas are not normally particularly heavy. The limiting conditions for the operation of this relatively small vessel, in which the design emphasis is on speed, are still to be determined in the light of experience.

0 New inflatable Tendering (Avon Rubber Co.

Ltd., Melksham, Wiltshire), designed to protect small craft at their moorings, came to the rescue of the organisers of the recent Boat Afloat Show when an oil slick threatened London's Little Venice. The slick drifted down the canal and rested against a solid boom at the mouth of the Little Venice basin. Although temporarily contained, the oil would eventually pollute the show site as the boom is regularly opened to allow passage for canal traffic. The answer was to somehow move the slick through the basin and into the canal exit downstream.

A 100 ft. length of the Avon fendering provided the answer. In its normal quayside role the fendering is ballasted with water and so, bent into a 'vee', it made an ideal boom which would not bounce on the water. First captured and sprayed with detergent, the oil was transported through the basin in the improvised boom paddled from a dinghy which also sealed the open end of the system. At the canal exit the oil was freed to float downstream where it subsequently dispersed..