SHIPPING (RADAR REFLECTORS) (Hansard, 5 November 1957)

§ Mr. H. R. Spence (Aberdeenshire, West)
I am very grateful to you, Mr. Speaker, for allowing me to raise the question of life-saving appliances at sea on the first night of our new Session. I am very grateful for this chance to raise this topic at a time when there is fresh in our minds two recent disasters at sea. During the past twelve years there has been a remarkable improvement in almost every kind of equipment that is carried for cases of emergency on all our passenger carrying boats and cargo boats and also in aircraft. Science, invention, new fabrics have all been used, and today, if one has to take to the boats in emergency, then, provided conditions are reasonably good, survival is almost assured, except for one thing; that is, that once away from the ship, or once the ship has sunk, all that has to be searched for is a small raft or a small boat, and the means of carrying out that search are either visual or, if the boat is fitted with radio, by means of direction finding or by radar. In the case of radar, there is a grave difficulty from which we suffer when scanning either from the air or from surface craft for boats or rafts where there is little or no metal work.
I am sure that there is fresh in the minds of everyone the terrible disaster to the German sailing vessel "Pamir", when so many German boys were drowned. When a few survivors were eventually picked up, it was found from their evidence—

§ Mr. Spence
It was found from their evidence that throughout the period after the sinking of the "Pamir" boats seeking to rescue the survivors had constantly passed within sight but did not manage to 147 pick them up on their radar screens. That is clearly borne out in the evidence of the survivors when they got back to Germany.
This very week-end there has been the experience of a young airman having to parachute into the North Sea. His dinghy was launched and then the weather clamped down, he could not be picked up again by radar or anything else, and he has not been found. It was the thought of these two tragedies that made me wish to raise on this Adjournment Motion the question of what could be done to try to carry on the improvement in life-saving that we have seen in the methods of buoyancy and the types of rafts and rubber dinghies now available.
There is the possibility of having a small radio transmitter which will send an automatic signal on which searching craft can home by means of directional radio, and there is radar. But radar has the difficulty and the inhibition to which I have just referred, that a rubber dinghy or a wooden boat will only show on the ordinary radar screen at about three quarters of a mile.
More recently there have been some further new developments and it has been found that radar behaves very much like a headlight beam. A headlight beam can hit a cat's eye in the road and bring back an image of startling brilliance to the eye. So in radar, if a suitable reflector is fitted—and it can be quite small—a bright image appears immediately on the screen although the main body of the object being scanned may be of a more or less insulating material. The tests carried out recently have shown that a small reflector, only about two feet across, will show an image on a radar screen five miles away almost as bright as that of a small cargo boat.
The principle of radar is that the vessel or the aircraft sends out a radial beam, the beam strikes the objective and is reflected back. So with this new reflector which has recently been developed we get the equivalent of the cat's eye stud in the road bringing back a bright beam to the eye, instead of the radar beam passing through the non-metallic objective.
148 There are some technical difficulties which arise. The perfect reflector for a radar beam is a flat plate, but if that plate is inclined out of the vertical plane by more than three degrees the responding signal disappears. For that reason these new reflectors have been made of what is called octahedral construction, which is, in effect, eight small triangular boxes, openside to the outside but joined together, so that the reflector is a conical affair which will always present to the incoming radar beam at least four triangular apertures. By means of reflection from these various three-sided cups into which the radar beam goes, a direct signal goes back to the sending station regardless of the amount of heel or sway of the boat, or object on which the reflector is carried.
I believe that we have reached the stage at which the technical difficulties have been largely overcome, and I suggest to the Minister that the time has come when his Ministry should perhaps take a more active part in developing this project and in finding out how far we have gone. There are obvious criteria which must be adhered to if a radar reflector such as I have described is to be useful. It must be light, it must be collapsible, it must be small, it must be effective at all angles, it must be foolproof and it should have a low wind resistance, because one of the important features in rescue which is sought nowadays is that once the craft in which the people are being rescued has been spotted, it should remain as near that point as possible. Naturally, if we had a large reflector which caught the wind, the drift would take the craft away and keep it moving. Low wind resistance is, therefore, a primary consideration.
I know that some reflectors have been built and tested, but I do not think that a test has so far been carried out with scanning from the air. It is also my impression that the tests which have been carried out on these reflectors have been when the reflector was hoisted on a small mast. That may not always be possible, and I should like to make three suggestions to the Minister.
The first is that he should ask his Department, or the section of his Department concerned with this matter, to make a thorough inquiry into what is available today and to have tests carried out 149 with a very small mast or no mast at all, scanning from the surface and scanning from the air; secondly, that he should publish the results of these tests and, thirdly, if he is satisfied that a reasonable type of reflector is available, that he should go as far as to recommend its use in one of the pamphlets which he publishes from time to time for the guidance of the owners of shipping. Here, I have his notice, No. M 401, about inflatable life-rafts. In it he refers to certain equipment as being compulsory and goes on to emphasise the value of certain other equipment as a recommendation.
I therefore suggest that the first stage is technical, that the second stage is to recommend the use of this equipment and to observe how it behaves in practice, and that the third, if he is satisfied, is to make these reflectors a compulsory fitting, if a suitable type can be found.
I am encouraged by the answer which the Minister gave me on Wednesday, 30th October. In column 208, in answer to my Question whether he would consider making some form of radar reflector a compulsory and standard piece of equipment, he is reported as having said: My right hon. Friend does not at present propose to make equipment of this kind compulsory, but he will certainly keep under review the desirability of doing so."—[OFFICIAL REPORT, 30th October, 1957; Vol. 575, c. 208.] That encourages me to urge him tonight to push on with experiments and trials and eventually to find the best answer to this distressing problem which arises month by month as one accident after another happens at sea. I am sure that it would be a great benefit if we could find ways and means of putting the radar reflector at the service of those in peril on the sea.

§ The Joint Parliamentary Secretary to the Ministry of Transport and Civil Aviation (Mr. Airey Neave)
I am very much obliged to my hon. Friend the Member for Aberdeenshire, West (Mr. Spence) for having raised this subject, which is of the greatest interest to all concerned with the saving of life at sea. I want to tell him straight away that for a long time my Department has recognised the potentialities of radar reflectors and their possible usefulness in saving life at sea. I also ought to tell him, as I told him the other day in 150 answer to the Question to which he referred, that at present we could not have them compulsorily fitted to lifeboats and life-rafts; nor could we recommend that until the tests which we are carrying out are more conclusive.
My Department's research group at the Admiralty Signal and Radar Establishment is carrying out these tests and has made great progress in the study of the properties of these radar reflectors in small boats and other forms of survival craft to which my hon. Friend has referred. We should have to be satisfied that some of the technical problems to which my hon. Friend has referred have been overcome. I think he will fully understand them, because he has described them very carefully and practically.
My hon. Friend said, and I agree with him, that there has been notable progress in the development and manufacture of different devices for rescue at sea. In the last few years we have had the invention of improved inflatable rubber life-rafts and dinghies. There have also been a number of inventions for improving the safe operation of ships, like the Decca navigator and true motion radar. We are making considerable advances.
I agree with much that my hon. Friend said about radar reflectors. It is quite right that the crucial factor in saving life at sea is early sighting by rescue craft of the lifeboat or life-raft, as the case may be. I quite agree that an efficient radar reflector would increase the chances of survival. My hon. Friend referred to the "Pamir" tragedy. I agree with him that it was a most terrible incident in the history of the sea but, in view of the inquiry that is being undertaken by the German authorities, I should not make any comment upon it at the present time.
A radar reflector is, at its most efficient, a useful and simple device. It is cheap, robust and foolproof. It has the advantage, from the point of view of training, that it has no electronic components and therefore is not too complex to be easily understood by those who have to use it. In its present form, however—though there are different types—it has certain disadvantages which I will describe in a moment. I confirm that the form that is the most efficient in developing a "blip" 151 —not a "bleep"!—on a ship's radar screen, is effective over a range of about five miles.
I think my hon. Friend will agree that there are many things to be stowed away in these lifeboats or life-rafts, such as supplies of food and water, and equipment such as distress signals, flares and torches for signalling. The size of the reflectors is a disadvantage in this respect and they will have to be developed in such a way that they can be easily stowed on board a survival craft.
It is probably true to say that radio is a more effective method of attracting attention than is a reflector, because it is effective over a longer range. I do not say that to discourage my hon. Friend or those who are concerned in the manufacture and development of reflectors. At present most of the aircraft carry radio and not radar, but B.O.A.C. is experimenting with reflectors when used in conjunction with aircraft. I think that answers the point my hon. Friend made in that respect.
Being rather heavy, this form of radar reflector has a problem in that it has to be hoisted above the level of waves to be in the direct line of sight to the radar scanner. In its present form this would be rather difficult to manage, particularly in rough weather. There is not at the moment any acceptable means of fitting it to a life-raft. The weight varies with 152 the substance of which it is made. Some of these reflectors are made of solid metal, some of bonded metal mesh and some of metallised fabric, and we have to find the right weight and the light material. A lightweight collapsible type has been developed, but at the moment I understand the shape of this version is not very suitable and renders it inefficient.
Another point I ought to mention is that the radar reflector is a wholly passive device: that is to say, the searching craft needs to be fitted with radar for the reflector to be of any use.
We have not yet produced an entirely satisfactory version, even experimentally, but we are continuing with these tests and making considerable progress. In these circumstances, while not wishing in any way to say anything to discourage the use of these radar reflectors, it is the view of my right hon. Friend—and my Department has consulted the Chamber of Shipping—that it is too early to fit them to all types of survival craft. We hope, however, developments will be more fruitful and that radar reflectors, when developed, will make a great contribution to the saving of life at sea.