[The following notes on rescues by helicopter have been issued by the Ministry of Transport and Civil Aviation for the guidance of yachtsmen.] AT present three types of helicopter are used for sea rescue work around the coasts of the United Kingdom: Sycamores and Dragonflies, which can rescue up to two persons, and Whirlwinds which can rescue up to six or seven persons. These helicopters can operate up to about sixty miles from the coast, but at that distance, because of fuel difficulties, they would not be able to remain very long before returning to base. They are subject to certain operational limitations; they are not flown at night; and they cannot be operated safely when the visibility is poor, nor when the wind exceeds forty-five knots.

When a "Mayday" message or a visual distress signal is received by the coastguard from a yacht in distress, steps are at once taken to send all possible life-saving assistance. This may include asking the nearest R.A.F.

Rescue Co-ordination Centre, or helicopter station, to despatch a helicopter to assist in the rescue.

Importance of Signals Once the helicopter has become airborne, how soon it locates the yacht and how effective its work can be, depends to a large extent on the cooperation of the yacht herself.

From the air, especially if there is a lot of yachting taking place in the area, it is very difficult for the pilot of a helicopter to pick out the particular yacht he is looking for, from the many he can see. unless that yacht uses a distinctive distress signal which can be clearly seen by him. One such signal is the Wessex daylight coloured smoke signal. This is very distinct from the air. A well trained Aldis lamp can also be seen except in very bright sunlight. The display of these signals will save valuable time in the helicopter locating the casualty, and may mean all the difference between success and failure.

It is essential that the yacht's position should be given as accurately as possible if the original distress signal is made by R/T. The bearing (mag. or true) and distance from a fixed object, like a headland or lighthouse, should be given if possible. The rig, colour of sails and hull should be included if time allows.

No Obstructions Aft A helicopter can lower on to or lift a man from a yacht provided that the yacht has no obstructions aft, such as standing back stays, and she either remains stationary head to wind or steams at a constant speed head to wind. If the yacht cannot comply with these conditions the helicopter may be able to lift a man from a boat towed astern on a long painter. For this purpose it may be possible for the helicopter to send down a rubber dinghy. On no account should the winch wire, when lowered to a vessel, be secured to any part of the vessel, or allowed to become entangled with any rigging or fixtures.

A helicopter close above a yacht carrying a large amount of sail may i send down sufficient slip stream to j cause the latter to capsize so that it is | always advisable for the yacht to shorten sail before the helicopter arrives over her. Without sail the slip stream will have no harmful effect.

Three Rescue Methods Helicopters are well practiced in rescuing survivors who are floating freely in the water. Three methods are employed. If the survivor is able to help himself a strop is lowered to him until it hangs about six inches above the sea and within easy reach.

The survivor should grasp the loop strop, slip one arm and the head through the loop followed by the other arm. He should then arrange the strop around the upper part of the body under the armpits, with the hook and D. ring in front. The toggle or webbing loop should then be pulled down towards the chest to prevent the strop from slipping. When this is done the survivor should give the "thumbs-up" sign to the helicopter crew.

The second and third methods of recovery are used when the survivor is unconscious or unable to help himself.

By the double winch method a helicopter crew man is lowered by winch cable into the sea for the rescue of the survivor. In the other method a helicopter rescue net is used to scoop the survivor out of the water.

Wireless Contact Helicopters are fitted with very high frequency radio. They cannot work on the medium frequencies. If a yacht, which is fitted with R/T, wishes to send a lifesaving message to a helicopter which is coming to its assistance and is unable to do so by visual means, the message should be sent by R/T through the nearest G.P.O. Coast Radio Station, addressed to the Coastguard.

On receipt the Coastguard will pass it to the R.A.F. Control Station for transmission on V.H.F. to the helicopter. In some places the Coastguard are themselves equipped with M.F. R/T, and maintain constant watch on 2182 kilocycles. In that ease a yacht could pass the message direct to them on this frequency.

A large number of Royal National Life-boat Institution life-boats are now being fitted with V.H.F. to enable the coxswain to speak direct to a helicopter working with the life-boat on a rescue service. If therefore a life-boat is known to be in the vicinity of a yacht the message for the helicopter from the yacht should be passed on M.F. (2182 kilocycles.) to the lifeboat for transmission to the helicopter.

Visual Distress Signals If the yachtsman in trouble observes that the helicopter is going to pass him by, or is on a course which will take it away from him, he should continue to make visual distress signals and, at the same time, if fitted with R/T, report the fact to the Coastguard stating the present bearing and distance of the helicopter from him.

The Coastguard will pass this information to the helicopter through its control station.

It is well to be advised of the particular dangers to be recognised when working with helicopters, in respect of their rotors. Helicopters keep clear of any obstructions such as masts, since any contact by them with the main rotor, and particularly the tail rotor, is disastrous for the helicopter.

Similarly, when survivors are landed from the helicopter they must observe closely the instructions given by the crew since there is an ever present danger of walking unwittingly into the tail rotor. This warning may appear to be overstating the obvious, yet it is surprising how simply and how often it is done..