Big Day at Little Turtle Island
by Andrew Turk, December 2014
It was one of those while you are there last minute jobs that my boss at Natmap Melbourne was apt to spring on me.† Sometimes while you are there meant while you are in that half of Australia, but this time, in early November 1972, it was just a quick jaunt a couple of hundred kilometres up the Pilbara coast from Dampier to survey a connection to Little Turtle Island, about 20 kilometres off the coast and 40 kilometres north-east of Port Hedland.
We had just returned from a secret mission to measure radiation levels at the atomic bomb test sites in the Montebello Islands and were hoping for a couple of days rest.† On the phone, the boss said that before heading south to connect more islands to the coast we should pop up to Port Hedland to do measurements to Little Turtle Island; he would send details by mail.† I asked if there were any likely problems.† He said:ÖNo major problems, except that the island goes under water twice a day and is just over the horizon, looking from the highest survey station on the nearby coastal mountains; Iím sure youíll cope.
True to his word, the details arrived in Port Hedland by post a day after we got there.† A telegram promised that a brand new large format Hasselblad camera would come by air freight, so we could photograph the island from the air.†
Map showing the location of Little Turtle Island.
Ed Burke and I were scouting around the industrial part of the town, looking for a solution to the just over the horizon problem, when we spotted a rusty painterís trestle, about five metres long, leaning against a shed in an open yard, looking un-loved.† We noted the location and returned to negotiate with the captain of the Fortesque V about hiring the boat for that night and the next day and night.† This boat was built for harbour work, but the captain said he could get us to Little Turtle Island and back.† The only trouble was that the waterside unions were red hot so, unless we wanted to pay a fortune to have them load the boat, we should come quietly after midnight and load it ourselves.
About midnight we left the hotel and drove to the port, borrowing the trestle enroute and arriving at the boat quietly with our headlights off.† We got the trestle and our survey gear on board and headed to sea in the early morning.† I must have been worrying about the survey as I couldnít sleep; that or it was the cold hard steel deck I was lying on.† A couple of hours before dawn I went into the wheelhouse and there was the captain, lying on a wide ledge between the wheel and front windows, back to the sea, steering with one hand and keeping an eye on the compass and depth sounder.
The captainís navigation was spot on and he had us anchored next to Little Turtle Island as it slowly emerged from the waves at dawn.† As soon as there was enough dry land, we started ferrying people and equipment onto the island, which ended up being a couple of hundred metres long and a bit less wide.† Our immediate aim was to establish a permanent survey mark on the highest part of the island over which the huge trestle would stand. Then we would survey to a second mark at the far end of the island to enable the size of the island to be accurately measured on the low-level aerial photography that Ed would take later that day.
I did a sun-shot to establish the direction of the line between the two survey marks.† Iíd done a lot of these in earlier years but was a bit rusty.† You need to put a dark glass eyepiece on the telescope each time before you look at the sun or the magnification of the theodolite telescope will mean the sun blinds you, at least temporarily.† Of course, you canít sight to the other end of the survey line without removing the dark glass, so it is continuously going on and off.† The trick Iíd learned from my first master surveyor was to keep the dark glass eyepiece in the fingers you use to re-focus the telescope, so you never forget to put it on before looking at the sun.
We were just able to get a Tellurometer distance measurement from the top of the trestle back to a party on one of the mountains near the coast before the turning tide started to shrink the island.† We retrieved all our gear and returned to the boat for a leisurely lunch and a bit of a nap while we waited for the next low tide.†
With about 12 hours between low tides, it was late afternoon before we could return to the island and resume our survey work.† We laid out white plastic crosses at the two survey marks just in time for Ed Burke to take the low-level aerial photos using the shiny new Hasselblad.† The plane did one final very low level pass over the island and headed back to Port Hedland.
The tide had turned and we completed another Tellurometer distance measurement and turned on our powerful light, strapped to the highest point on the trestle, relieved to hear, when the radio told us, that the shore party could see it.† Measuring accurate horizontal angles between mountains, or in this case between a nearby mountain and our island, takes hours and this was still underway when the returning tide meant we were running out of time and island.
Having evacuated most of the people and equipment to the boat, the captain and I had the dingy tied to the trestle with water lapping at our feet, the light shining brightly overhead and the angle measurement still not finished.† We had to grab the light and abandon the trestle when the water was half a metre deep and jump into the dingy.† By time we got back to the boat it was very dark, with the wind up and a considerable sea running.† With difficulty, we got alongside and tied a rope to the dingy.† However, when scrambling aboard the boat the dingy was swamped by a wave and started sinking.† Quick as a flash the captain dived over the side to upend the dingy and save it and the outboard motor.† My heart was in my mouth as he thrashed about in the boiling sea and I didnít dare think of the consequences if we couldnít get him back on board.
The captain managed to save the dingy and outboard motor and dripping wet headed for the wheelhouse.† I climbed through a hatch and into the hold of the boat to make sure all the survey equipment was safely stowed.† Sadly, I didnít get out of the hold till we reached Port Hedland in the small hours of next morning.† I was just about to climb the ladder when the captain started the engine and turned the boat towards shore, side on to the strong swell.† I was knocked off my feet and lay on the floor getting increasingly seasick.† I remember times during that terrible night when waves crashed over the boat and water gushed through the partly open hatch cover and drenched me.† I thought that perhaps the boat might sink but felt so sick I couldnít climb the ladder, even if my life depended on it.
We were all a bit tired, and myself somewhat bruised, from that big day on Little Turtle Island, but we had done the measurements and taken the photos.† My telegram to my boss advising him of this, added that we were leaving town and heading down to Onslow to connect in more islands, hopefully all visible from shore and dry at high tide.