From the report regarding Sunderland NZ 4117 at Tarawa 15 April 1961
On a normal visit to the RNZAF base at Tarawa the Sunderland had been tasked to carry out a patrol en route. This meant the arrival at Tarawa was in the late afternoon.
The aim was to alight just past the main island of Betio and parallel to its neighbour Bairiki.
By the time the aircraft arrived fuel was getting low, there were reserves, but the aircraft was not going anywhere but here, right now.
The aircraft had arrived just as a serious tropical line squall hit the atoll. These things can be of great fury but are normally of short duration.
But this one had hung around for a while delaying the landing. Eventually, it abated a little and, although the water was still very rough, the captain decided the time had come to land.
The lagoon at Tarawa is large, but is reasonably shallow and sheltered, particularly from the east, so open sea swell was not a problem.
Because it is so large and the islet periphery so low lying, however, there is ample fetch for the wind to whip up a significant short, steep sided wave inside the reef.
There was no risk of being thrown off the surface by a swell, but, coming the other way, at a critical moment was a large, steep sided wave.
Water is less compressible than dirt.
The aircraft ploughed on, bucking energetically in the chop. Then it began to sink quite quickly.
The keelson had broken under the bow compartment and the planning hull was breached.
The water remained very rough. The break in the keelson could not be dealt with from the inside, and there was no prospect of inspecting the damage or doing anything about it from the outside until the aircraft was securely moored.
Meanwhile, the water was coming into the bow compartment at a great rate.
The APU [Auxiliary Power Unit - a small engine driven generator] pump had, as expected, worked briefly then choked, it was useless.
The hand pump could not keep pace with the inflow although it continued to be used to reduce the effects.
The working stroke on the hand pump is the up stroke, its design assuming an upright stance and the use of the back muscles.
But it was not possible to stand upright in the bow compartment. Cramped and stooped under the low deck head the heavy pull stroke fell to the triceps alone, arms akimbo.
With the aircraft still not moored and heaving in the waves, in the confined space and the high temperatures to be expected in the tropics, those doing the heavy work soon succumbed to sea sickness.
They had no choice but to continue, knee deep in sea water in which now floated their own vomit, which threatened to spill over the isolating bulkheads into the rearward compartments.
This was heroic stuff, but it was expected of the crews as necessary, and this crew had a vested interest.
When the aircraft was finally moored and the squall had subsided, crew members dived over the side to inspect the damage from the outside.
After making an impression of the breach with a large piece of Plasticine they reduced the leakage rate for the time being with coir mats.
A Plaster of Paris mold was constructed from the Plasticine mold. Finally they melted a considerable amount of solder and formed it, using this mold.
When it solidified the metal was bolted to the damaged area, stopping the leak altogether.
A couple of weeks later the crew had shored up the weakened area with pieces of timber from the inside.
NZ 4117 made it back to Laucala Bay under its own steam. It was decided that, due to the soon to be enacted withdrawal of the Sunderlands, not to repair it but reduce it to produce [scrap].