Golfito RTI
Elders & Fyffes t.s.s. ''Golfito'' was equipped with a Marconi ''Radiolocator IV'' radar which was fitted with R.T.I. That abbreviation stood for Radar Track Indicator, an early version of the true motion facility that eventually became common on all radars. It took the form of a small control unit slung, pannier fashion, on the pedestal of the radar display, and an enormous cabinet fixed to the after bulkhead of the wheelhouse. This contained what was in effect an analogue computer, fed with the speed and heading of the vessel (either manually by the user, or automatically through links to a speed log and a gyro repeater). Further information about tidal direction and speed could be input to the control unit by the user, if required.
All this information about the ship's movement through the water was used to move the ship's position on the radar screen in relation to the radar picture. So instead of the ship's position being fixed in the centre of the screen (or permanently off-set towards the cir***ference, the point representing the ship tracked steadily across the screen in the direction that the ship was heading and at a speed equal to the ship's speed.
All very standard now but in those days it was fairly novel and made more exotic since it was executed using thermionic valve (tube) technology. For those not old enough to have met equipment that did not use solid state electronics, it should be pointed out that thermionic tubes suffered a gradual deterioration in performance with age. Rather like a light bulb. This made the equipment that employed them subject to rather less than perfect reliability. Of course the more valves that the equipment contained, the more likely it was likely to fail at sea.
Now the ''Radiolocator IV'' radar itself was full of valves, somewhere between 70 and 80, if I remember correctly. The RTI computer contained even more. So it was not surprising that after leaving Avonmouth for the West Indies we were no more than a n hour our two after dropping the pilot when a call came through to the radio room that the radar was ''playing up''. The Chief R/O, P.J. Kelly was very unsure of himself where radar was concerned - he had gone to sea long before its invention. When it came to analogue computers, he was way, way, out of his depth. So he dreaded problems involving the radar when it was being operated in the true motion mode. He impressed on the Mates that RTI was an optional facility, to be used only in special cir***stances. Of course they took this with a huge pinch of salt and were attracted to the radar and its ''optional facility'' like kids to an amusement arcade. No opportunity was missed to set it going and to try to get the speed and tide settings just right, so that the land stayed absolutely still, with no smear, while the ship's origin sailed smoothly across the screen.
PJK pointed at me and said, ''Come with me, Mister.'' When we got on the bridge, the Second Mate pointed to the radar and said, ''Have a look at that, Sparks, it is tracking at 50 knots, and it's going astern!'' And sure enough, it was. We were zapping back towards Avonmouth, crossing the screen in seconds before resetting instantly, only to resume our mad dash up the Bristol Channel in reverse. Kelly's face was a picture as we set to to remove the covers from the RTI computer unit and reset the gate switches so that we could begin measuring valve feeds with the plug-in meter provided. I was reading from the faultfinding information in the handbook and PJK was operating the meter. After about half an hour of this, on hands and knees on the wooden deck, things were getting a little fraught. It is one thing fault-finding in the seclusion of the Radio Room but quite another in the glare of the wheelhouse, under the interested, if amused, gaze of the Second Mate, a couple of apprentices, the QM and the lookout who spent at least as much time watching us as looking over the dodgers. I had never seen the RTI before and PJK hadn't a clue. He began to sweat and became very red in the face.
It was at this moment that the Master, G.M. Roberts appeared. ''How are things going, Sparks?" he enquired. ''Can you hurry it up, we need the radar as visibility is reducing?''
''I'm doing my best Cap'n,'' was Kelly's rather tetchy reply, ''but this is very complex equipment, you know.''
To which GM's response was a light-hearted, ''Not to worry, it was working fine when we left the locks at Avonmouth, so there can't be too much wrong. It's probably just a valve.''
The reaction from Kelly was explosive. The level and tone of his voice rose rapidly.
''Just a valve? JUST A VALVE? AND JUST WHICH ONE OF TWO HUNDRED F*CKING VALVES DO YOU SUGGEST IT IS?
To his due, the Master recognised that the situation was not being helped by his presence and made a tactful withdrawal. About half an hour later we found the fault and restored the system to normal and left the bridge. Kelly never spoke of it again but all future complaints about the radar were passed to me for action. It must have been because I could read the book, because it certainly wasn't anything to do with my knowledge of radar. Prior to joining the ship I had only read about it, never seen it in action. Of course as soon as I signed off that ship, I was sent to Cardiff on a two-week ''Radiolocator IV'' training course. And equally predictable is the fact that on completion of the ''Radiolocator IV'' course, I was appointed to a ship with a Marconi ''Quo Vadis'' radar (never, ever, had a course on that!)