Talking of flying boat take offs, the following comes from a 1945 report of QANTAS Empire Airways non stop operations during the war from Perth, Australia to the now Sri Lanka using Catalinas. Chief Pilot Capt. L. R. Ambrose was author, "A Brief Outline of Indian Ocean Operations".
As for the terminals, the take off area at Perth could have hardly been improved upon. Clear stretches of water up to two and three miles were available with no obstacles higher than 300 to 400 ft. within fifteen to twenty miles of the site. Very occasionally were delayed due to rough water when a strong and gusty wind blew in from the southwest.
At Koggala, the take—off was not so simple due solely to the limited area of the lake. When our services first commenced operating from this lake, the difficulty did not present itself in spite of our having noted that there was only one dog-leg take-off path as it was the period of the southwest monsoon, and the take-off path lay only slightly out of the quite strong south—west to west wind which blew continually. With the coming of the north—east monsoon, however, ushering in as it did, long periods of calm or light cross winds, a special technique had to be devised to get the rather heavily laden boats into the air.
It was noticed at once that the heavy aircraft lay very low in the water, and that if the throttles were opened normally, the bow compartment would build up an ever-increasing mound of water ahead of the aircraft, with a consequent loss of acceleration. If the throttles were opened as quickly as possible, consistent with smooth power development, whilst the control column was held hard back, the large amount of air-screw slip acting on the quite large elevators would blow the tail down, which allowed the nose to slide over its water barrier.
Because of the drag of the large aerofoils, it then became urgently necessary to return the control column to central. Any movement of the controls from central had a marked effect on the acceleration. At the same time, however, it soon became evident that the tail needed to be raised in order to decrease the angle of attack of the mainplane and to assist the boat to the step. The most effective way to do this was to adjust the elevator trim tabs very coarsely. In case this is not clear, perhaps it may be understood more fully if I point out that only when the aircraft reached such speed as made the controls fully effective, could the tail be raised in the normal manner. Any movements before this period would only delay its arrival by increasing the drag and only long experience and consistent watching of the air speed indicator would show its arrival. Watching for this speed would have been just something else to watch for, whereas by altering the trim tab, its drag was negligible and yet it announced automatically the arrival of the effective speed by itself acting upon the elevators and raising the tail. Immediately this movement was felt, the trim tab had to be adjusted back to the take off setting. With practice, this could be done quickly and without reference to the adjustment scale. By now, in our take off, the floats should be raised and the post—hump porpoise had commenced. This latter was normally stopped by a slight rearward movement of the control column, but in conditions of flat calm, it was found advantageous not to damp it right out, as the slight rocking motion tended to introduce air under the planing bottom, and so help to unstick the boat.
From the time the craft was on the step, no further special technique was required, as it quickly accelerated to the point where it became airborne. In glassy calms up to 115 seconds have been taken, but the average was 90 to 100. Using the special drill this time was cut down to from 70 to 80 seconds. Taking the worst of the latter and comparing it with the best of the former times, an advantage will be seen of 10 seconds, which, when converted to horizontal distance over the lake reckoning on a speed of 60 miles per hour (and the Catalina was going faster than this at 60 to 70 knots) shows that approximately 900 feet was saved, which in a limited take off area, such as Koggala, represented a very valuable saving.