AN article by my predecessor on the use of wireless in life-boats appeared in the number of this journal for December, 1937. It was then eleven years since the Institution had begun its experiments with wireless by installing a wireless-telegraphy receiving and transmitting set in the life-boat at Rosslare Harbour, Co. Wexford. That is the only wireless telegraphy set that has been put in a life-boat, and it continued in use until June, 1948. Our next experiment Mras with radio-telephony in 1929, and when that article was written in 1937 we had twenty-six boats with radio-telephony sets for receiving and sending messages, and three with sets for receiving only.

Ten more years have now passed.

Much has happened in those ten years; * good deal has been learnt from the experience of the war; many improvements have been made in the design and construction of radio apparatus; and many more life-boats have been fitted with radio-telephony; but the conditions under which wireless works in life-boats, .and the limitations on its use in them, have not greatly altered in the past ten, or indeed in the past twenty years.

Protection Against the Sea Our first and greatest difficulty has always been that wireless apparatus must be very carefully protected from the water, and that a life-boat is a small boat which has to do her work in the worst weather, and has often to travel smothered in the seas, with her decks awash and her cockpits filled.

Then there are very serious limitations in the size and weight and power of the apparatus that can be used, and the height of the aerial which can be carried on a life-boat. The chief use of wireless in a life-boat is to keep her in touch with the shore when she is at sea. She does it through the shore wireless stations of the General Post Office, and through certain lighthouses, lightvessels and coastguard stations.

These stations have not powerful transmitters like the B.B.C.; most of them work on a fraction of one kilowatt, where the B.B.C. is working on 50 to 200; their messages have to be picked up on life-boats by aerials which, to be really effective, require much higher masts than any life-boat could carry; and they have to be heard in the midst of the noise of wind and sea and engines.

Those who, in the silence and comfort of their own rooms can, through a powerful transmitter of the B.B.C., hear with ease a programme from the other side of the world, can hardly begin to understand the difficulties which a life-boat mechanic—sitting at his controls above the engine-room in a howling gale—may have in taking a message from a wireless station only a few miles away.

During the War That was the state of affairs at the beginning of the war, in September, 1939. Immediately war was declared all transmitting sets, except in lifeboats on the coast of Eire, had to be put out of action and sealed. Lifeboats might listen but they must not speak. Nor would the Government allow any more boats to be fitted with wireless. This continued for four months. Then life-boats were allowed again to send out messages, but they were warned that they must say nothing which could give information to listening German submarines. The Institution was also allowed to equip more boats, and during the war twelve were so equipped. The Admiralty also fitted seven of our boats, which had no wireless, with receivers as used on motor cars, so that the coxswains might be kept in touch with the naval officers in- charge on shore. Some of these receivers are still in use. The position at the end of the war was that out of the Institution's 151 motor life-boats, 70 had radio-telephony; 57 of the 70 had sending and receiving sets; 13 had receiving sets only.

Up to this time transmitting sets could be used only in life-boats with cabins, and they had now been installed .in nearly all the cabin boats. The 13 life-boats which had only receiving sets were open boats. We had found it possible to put the receiving sets in 'water-tight cases which could be fixed under the canopy covering the engine controls, but it was much harder to make the transmitting set watertight.

It required a case larger than the canopy would take.

A New Specification The position now was that if we were to make any further advance, and if we were to be able to equip every life-boat with complete radio-telephony, we must have a watertight receiving set of a size which could be used in open boats.

During 1946 we examined a number of existing sets, but found none with the four essential requirements: that it should be waterproof: of small size; able to give a sufficient range with the small aerial which was all that a lifeboat could carry; and simple to work by unskilled operators in any conditions of weather and noise. So the Institution prepared a specification of its special needs. It wanted a set consisting of four small units: a transmitter, a receiver, a power pack to convert the power from the life-boat's electric battery into the ' different voltages needed by the transmitter and receiver, and a remote control, or extension.

The extension must be for both transmitter and receiver, and the receiver and the extension must have loud-speakers built into them. In the case of cabin life-boats, the transmitter and receiver would, as before, be put in the cabin, where they would be effectively protected from water. In the case of boats without cabins, they would be in water-tight cases either in one of the end-boxes or under one of the sidebenches in the cockpit. The remote control, or extension, would be in the roof of the canopy, where the motor mechanic would have it close by his head as he sat at his engine-controls, and it must be proof against continuous drenching with sea-water.

The Advantage of Crystal* The specification also asked for sets fitted with crystals to control the wavelengths.

There were to be four, and one of them was to be set to the wavelength of the international distress signal. They were chosen because a crystal has the advantage of maintaining a constant wave-length. By turning to it the operator gets at once, without searching, the wave-length that he wants.

In the earlier sets the aerial was a single wire running from a small mizzenmast to the top-mast, then down to an insulated lead-in trunk and so to the set in the cabin. The new set was, where possible, to operate with a vertical rod aerial, though, in some boats, the normal aerial between the masts would still have to be used because of difficulties in transmission. The advantage of the rod aerial was that it would be independent of the mast and its running gear and would not be affected when—as often must be done in heavy seas—the mast is lowered before the life-boat goes alongside a wreck. If it should happen, with the life-boat plunging alongside a wreck, that the rod aerial had to be temporarily preventing it from spreading, carries it ve times further. The loud-hailer is a megaphone which, with the help of electricity, carries it ten times further than the megaphone. A man speaking into it in his ordinary voice will be heard 500 yards away. Even in the noise of a gale it enables the coxswain to speak clearly to the men on the wreck and do by word of mouth what before had to be done by flags or a signalling lamp. We now proposed unshipped, this could be done without difficulty.

The Loud-Hailer We also proposed to combine with the new transmitter one of the most useful inventions of the war, the loudhailer.

After experiments with various makes the Institution had decided to adopt it in all life-boats, and it had already been fitted in a number of them. Before the war the only means of increasing the range of the human voice was the megaphone which, by that this loud-hailer should work off the amplifier of the wireless transmitter, instead of independently.

We sent this specification to several firms, and Coastal Radio has designed a set which meets our needs. The first experimental set was fitted in the Appledore life-boat in May. 194T.

There it was thoroughly tested. More sets were ordered and now we have four in life-boats with cabins, and two in open life-boats. They are all working satisfactorily. They are small, light and very simple to work. It is easy with them to give and receive messages up to fifty miles, under almost any condition, and under favourable conditions over much greater distances; and the motor mechanic, simply by moving a switch, can pass at once from speaking through the radio transmitter to the shore to speaking through the loud-hailer to the wreck.

Complete Equipment in Two Years The new sets, like nearly all the old, are not bought by the Institution but are hired from the makers, who undertake to maintain them. Instead, however, of only calling in the firm when there is a failure, it has been arranged for all sets to be inspected every two months.

The present position is that of the 154 motor life-boats in the active fleet 80 are now equipped with transmitting and receiving sets, and 11 with receiving sets only. In the reserve fleet of 14 boats, two have transmitting and receiving sets. Besides the six boats in the active fleet which have the new sets with loud-hailers attached, there are 33 boats which have loudhailers working independently.

We have now radio equipment which can be used in every type of life-boat.

New boats will be fitted with it, and the old sets in boats on the coasts will be replaced with the new as circumstances allow. We expect to equip the whole fleet with the new sets in about two years.