Research and Development Officer, RNLI IMAGINE A JANUARY AFTERNOON. Not much wind, but a cold front forecast; the light will fade in a couple of hours; wind and sea will be getting up and the temperature is dropping all the time.

Not ideal conditions for a winter inshore lifeboat service, but there's no time to think about that: the maroons have just gone up. A boat is reported in trouble close inshore about eight miles down the coast. So, on with the waterproof gear, and lifejackets, and off goes Atlantic 21 and crew; but with wind and spray, faces and eyes are going to take a lot of punishment.

Lifejackets have been a symbol of lifeboat crews for well over a hundred years. The present lifejackets are the result of an intensive development programme in the 1960s (see 'Medical Arrangements in the RNLI' by Geoffrey Hale, THE LIFEBOAT, volume XLIV, number 454) and are now capable of self righting an unconscious wearer.

Protective clothing has changed considerably from the original stiff oilskins and sou-wester, although with modern materials and design the choice is so wide that finding a single off-the-shelf product which suits all ILB crews has not so far been possible.

Thigh boots and waterproof gloves are available to crew members, but again personal tastes vary considerably, so not all are satisfied. Since most waterproof suits have hoods, the face is the only part of the body not provided for; this was a problem which had to be tackled because, apart from any other consideration, one fifth of total body heat loss is via the head.

A recent programme of initial research, followed by tests and development trials, has resulted in the adoption of a special RNLI visor mounted on a motorcycle type helmet. Armed with this headgear it is intended that the wearer will be able to see better, keep warmer and remain drier in the sort of conditions likely in the hypothetical service referred to above. Bonuses of head protection when working alongside the casualty or in a capsize among rocks, and ease of being seen, are also intended.

In an actual service under such conditions the first problem would have been the cold, with occasional bursts of spray aggravated by a chill factor due to the speed of air over the face. If travelling at 30 knots boat speed into gale force winds this would result in a relative wind speed of over 60 knots.

While some might be able to take this treatment for half an hour or possibly more, most would have frozen faces and running eyes and it might be essential, for safe and efficient navigation, to ease the speed. Balaclavas, hoods or lower face masks help but are not the total solution.

If, in the hypothetical service, it was then to start raining, the droplets would sting the face and especially the eyes.

Rain is generally reckoned to be more aggravating to crew than spray, presumably because, being sporadic, spray can be seen coming and the head can .

be ducked. The worst treatment the bare face can receive in an ILB is driving hail; the crew just cannot see ahead and speed has to be reduced, for safety, to a few knots.

Soon after the ILB was an established part of the lifeboat scene, faster offshore lifeboats were introduced, the first being the 44' Waveney self righting class, to an initial US Coast Guard design. With their greater power and speed compared with conventional boats it was soon found that, at speed in rough water, the crew had to be aware of the lively motions due to wave impact if injury was to be avoided. Fairly soon a suggestion that helmets be issued for use in these boats was accepted; the USCG already used helmets in their own 44' boats. A one size helmet with an adjustable headband and chin bridle incorporating cut-outs to enable crews to hear one another was eventually selected. These helmets were made available for all other self-righting lifeboats since it was felt that the violence of capsize and self righting in enclosed cabins and wheelhouses could result in severe injury to the head. When used with the optional press-studded peak, this helmet also gave slight face protection to inshore lifeboatmen who had no windscreen or wheelhouse for shelter.

In 1974 the National Research and Development Corporation (NRDC) offered help to the RNLI in the blanket form of 'encouraging technical innovation'.

No specific field of aid had been suggested but, during the followingyear, a wide range of possible subjects was narrowed down to 'clear vision in adverse conditions'. By the end of 1975 a good deal of preliminary work had been completed and an agreement drawn up between NRDC, the RNLI and the Marine Technology Support Unit (MATSU) at Harwell, specifically 'to develop improved goggles or visors for use in lifeboats'.

Initially it was thought that windscreen wipers and clear vision screens should also be investigated, but after discussion it was agreed that if research were limited to the individual visor/ goggle problem, less hardware and experimental testing would be involved, making for economy. Any knowledge gained about materials, coatings and possibly shapes might well be of use, later, to help in solving the throughwindscreen visibility problem. In addition it was hoped that if the visor/goggle vision was improved, a potential market might be opened up in the powerboat field, high-speed yachting, motor cycling and in the Services.

Once it was established that visors were to be developed the work went ahead in three broad stages: 1. Initial investigations and trials Inshore lifeboatmen who had obtained their own headgear were consulted and an assessment made of their selections and of other commercially available helmets and visors. MATSU undertook a literature survey of materials, waterrepellent coatings and water-shedding devices. NRDC investigated patents and reviewed the potential market. Trials were arranged in an Atlantic 21 for MATSU staff accompanied by RNLI technical and operational staff. About a dozen combinations of commercial products and a number of specially developed RNLI-produced visors were tried out.

2. Tests, reports and patents MATSU arranged for a series of studies and some laboratory tests, (continued on page 267).