Post by RobinK on Jan 19, 2007 23:31:18 GMT 12
SUNDERLAND ON PATROL, NINETEEN FIFTYSOMETHING. PART 1
Flying Sunderland "boats" on maritime patrol seemed always to mean getting up at an unsociable hour. Perhaps because they cruised so leisurely, it was necessary to take off at the crack of dawn, or earlier, in order to be sure of doing anything very much before nightfall.
Having arisen however reluctantly, the immediate purpose is to satisfy the engrossing hunger that is a part of such small hours. A sympathetic system makes available a breakfast of monumental proportions at the Combined Mess.
Then to the squadron for briefing. Close-in, lights on the hard-standing reflect on the water in the pre-dawn stillness. Farther out, the water ripples in light airs coming down the channel. Ground crew are busy. Marine Section tenders fuss around the jetty, and ruffle the surface between shore and aircraft. The control launch is readying to put out.
In the operations room the navigators plot the patrol on their charts. The weather will be mostly broken cloud, some showers, wind on average 350 degrees at 15 knots, except for a front lying across the route about five hours out. They hunch over their computers - not the modern digital variety, but a device with a circular slide rule on one side and a wind-and-course triangulation gizmo on the other.
The flight engineers worry about fuel load and all-up weight; and the signallers about frequencies, Morse keys and code books. The pilots worry everybody including themselves, quiz the ground engineers, and eventually condescend to sign the maintenance release and the flight authorization.
It is not yet light as they go to the jetty, to the barge, and to the aircraft. The captain asks who has the flight rations - meaning what is in them? It will, after all, be a flight of more than twelve hours and he needs to savour the possibilities in advance.
The great white aircraft looms up in the half-light. “Watch it” calls the captain to the coxswain as the barge noses under the overhang of the wing, in his early morning irritation making an attempt to stamp his authority where it does not belong. The marine diesel bubbles briefly under power as the boat is brought to a halt with a scritch of rubber when the gunwale fender kisses the side of the aircraft. The mooring buoy streams out ahead, though the aircraft lies awkwardly askew under the competing influences of the tide and a now-rising breeze.
Aboard, the aircraft stinks. It has been tightly closed up overnight. It is redolent of salt water, mildew, verdigris, oil, fuel, sweat, old cooking and a primordial blend of liquids slopping in the bilges. Hatches quickly swing open to admit fresh air.
The navigators lug to their station on the upper deck their heavy bags of charts, logs, sextants, pencil boxes, protractors, dividers and other symbols of their art. The signallers and engineers repair variously to their stations and to other parts of the hull on their appointed pre-flight duties. One goes to the galley on the lower deck.
The Sunderland was always in two minds whether to be ship or aircraft. In New Zealand service as the Mark V, it was designed and built by a shipyard, Short Brothers and Harland of Belfast. Of semi-monocoque construciton it was a four-engined high-winged monoplane, so it was said. But it had a bridge, a wardroom, a galley, a keelson, chines, both a nautical and an aeronautical almanac (and nautical and aeronautical charts), a fog bell, an anchor and a leadline.
The galley was a grand misnomer for a cramped space where one cooked upon two Primus stoves on a bench with a sink. Hard beside was a ladder leading to the upper deck. This and the other compartments ran full across the width of the hull.
The galley had a sizeable hatch either side. Beneath each was a large container for the sea drogues. The aircraft had no sea rudder nor water brake. On the sea it was steered and the speed was controlled by a combination of asymmetric power from the engines, the air flaps, the ailerons, the air rudder, and the drogues which were launched by hand from the galley hatches. These were windsock-shaped canvas sleeves with a thin wire hawser cleated to a frame on the bulkhead. Once deployed, the force of the water flow usually meant they could not be recovered until the mooring was complete - and even then with difficulty in a strong-flowing tide. They had a spill rope attached to their tail so they might be collapsed again if need be, but it seldom worked reliably. It was better to assume that once deployed they stayed deployed, which normally meant the pilots had to call the one-shot moment with care.
Next forward of the galley was the wardroom; also a grander name than the compartment deserved. There was a bunk down each side and a fixed table with fold-down leaves in between. Naturally enough, even with the leaves propped open the surface remained out of reach of a diner of normal proportions seated on the bunks; and the height was as badly matched. To give a feeling of home, however, the table was finished in a tasteful light green. The deck was bare dural, though with worn remnants of green paint, strengthened underneath by stringers, their skeleton outline emphasised by depressions and bruises in the much-worked surface between. The walls were bare dural as well, being the thin outside skin of the aircraft. No padding, no lining, no gestures to livability; just the skin marked out by vertical constructional ribs and horizontal longerons, punctuated by tastefully rounded portholes. The wardroom became an action station on operations, for it housed the sonobuoy acoustic receiver.
Throughout the lower deck and beneath the decking, a bulkhead sealed each compartment from its neighbours. Above the decking, doorways between were fitted with swash doors extending the watertight isolation of compartment from compartment to about three feet above the deck. These could be opened but were normally dogged shut. To pass through one could open the swash doors after wrestling with the dogs or simply step over them, the latter for preference, though at some risk to the person, especially those shorter in stature. The lower deck panels had ring latches so they could be lifted to get at the bilges and dark spaces beneath, should the need arise.
Aft of the galley was the bomb room. This contained marvels of expedient engineering. In a flying boat, breaching the planing hull to provide such as bomb or torpedo doors is a design challenge. Here, the designers had chosen not to tackle the challenge head-on, but to avoid it. The weapons were carried wholly inside the hull. Bomb racks were mounted along the lower line of the wing two decks up. To load or reload in flight there was a winch, hand operated by chain, to lift the ordnance from the floor to hook up to the racks.
So far so good. There remained the problem of getting the racks outside and clear of the airframe so the weapons could be dropped. The design engineer had provided an ingenious system in which, one supposes, as each problem was solved another arose to be solved in its own way. Sequential engineering.
The racks ran out on rails beneath the wings, powered by electric winch (or if that failed, by a crank wound by hand). When the racks were retracted inside, flexible strips were drawn over the rails set into the under-surface of the wing so the airflow would remain undisturbed by the discontinuity.
But with the racks inside and needing to get outside, the fuselage walls were in the way. Very well; put a door each side. These were not ordinary doors, however. They could not be hinged outward for reasons of slipstream, nor inward for reasons of space. So they slid vertically in a frame, from high up under the wing root where the bomb racks were poised on their rails.
It was necessary to seal around these doors, otherwise the spray would come in during takeoff and landing. Therefore the mounting frames were designed to move bodily inward to break the seals, whereupon the doors could drop vertically downwards along guides in the frames. The release latch to effect this was operated electrically from the cockpit, with a local manual release for emergencies. The tensioners that sprung the frames clear, breaking the seal and giving the doors room to drop, were none other than stout rubber bungees - and the doors were similarly cushioned as they fell to the limit of their travel. The original bungee jump - eat your heart out A.J. Hackett!
Aft again was another compartment with bunks, graciously called the after crew compartment. From there the floor sloped up toward the tail and the rear gun turret, with a chute nearby for dropping flares and smoke markers. This, too, had an example of thoughtful engineering design, practical though looking slightly home-made. Should a flare become jammed in the chute and burn, the results might be serious. The safety device was a broomstick, conveniently clipped to the wall, which one could use to persuade the errant flare to depart.
Nearby there was another monument to the nature of this beast. On the starboard side near the rear external door there was a box. In it was an array of rubber stoppers in various sizes with which to plug leaks in the planing hull. Likewise it housed a number of heavy coir mats. And there were generous wads of ordinary plasticine for the same purpose (but not in bright kindergarten colours, only regulation dingy grey-green).
Turning and moving forward again there was a step to the upper level via a hinged bridge between fixed platforms on each side. These were the waist gunner's positions. Wide hatches opened to enable a hefty point-five Browning machine gun to be mounted on a pintle each side, the barrel sticking out into the airflow. It was a free-firing weapon; if the gunner forgot to screw in the safety stop he was quite likely to shoot up the wing float in the heat of the moment. It did happen.
Moving on forward we mount up a ramp and through the central box wing structure to a tiny door at the back of the crew deck. On this ramp, to the right, was a significant device. The Sunderland in RNZAF service was equipped with the ASV Mark 6C maritime radar. But with gun turrets at the nose and tail of the fuselage, and the planing hull underneath, there was no place for the antennae but the wingtips. A radome blister was therefore attached under each. That presented a further difficulty. The radar had to look down to the sea, but from each wingtip the hang of the fuselage blocked out a goodly part of the sweep. The solution was a hefty waveguide switch which transferred the radar energy from one wing to the other at the appropriate moment each scan. With the radar running it did this with a noisy clack-clack, at least loud enough to be audible above the roar of the engines, unattenuated by the thin aircraft skin.
Moving forward again (and being careful not to fall through the open hatch into the galley below) there was the engineer's desk on the right and, stepped just forward of the front wing spar, the signaller's desk on the left. The engineer faced aft watching his panel with the engine health gauges and all of the fuel gauges and supply cocks. The signaller faced forward, presiding over an array of heavy black boxes by Marconi, with mysterious dials and knobs and, under the covers, tuning devices curiously named pecking motors. Fixed to the desk was a Morse key. Though the aircraft used HF voice modes extensively, Morse procedures were a prominent and necessary part of communications. Some signaller aficionados disdained the supplied key, and fixed their own personal "bug" in its place. This was a clever semi-automated two-way switch operated between forefinger and thumb. When the lever was moved one way a weighted spring trembler produced a stream of dots, whilst for a dash the lever was moved the other way. It provided for greater Morse speed, though in turbulent conditions it could be more difficult to use without stammer than the standard key.
Above and centre was the astrodome. In the air this was a good lookout point besides being the mount for the navigational sextant. On the water the hatch and dome could be removed for egress to the top of the fuselage and the wings. At the rear edge of the hatchway was the engine starting panel, complete with priming pumps, selectors and starting booster controls. However, unless one was an eight-foot giant one could not see out of the dome or the hatch from the flight deck. There was provided, therefore, a stowable platform to stand on.
Moving forward, the navigator was on the right and the tactical navigation table on the left. The latter had a ground position indicator, a machine which projected a crossed arrow onto a chart from above, purporting to represent the aircraft's position during ASW manoeuvres. It was intended for short-range tactical use only, being an analogue device of bell cranks and pulleys which was reliable for all of a minute or so after it was set up.
On the right was the radar tent, just behind the co-pilot's seat. It had black curtains all round, which had to be closed in daylight if the operator was to make much of the screen. It was also a nice place for a kip.
Forward yet again to the pilots' seats; or the "bridge", since this was a boat. Instruments on the panel, throttles and other engine controls in between the seats, flying trims overhead, and switches placed at random all around. Between the seats and just aft of the throttle pedestal, another opening led below to the bow compartment.
On the deck to the left of the captain's seat was the standby P-type magnetic compass; and near it the bomb door and rack actuation switch. If sufficiently ham-footed it was possible to kick this switch into action with the left heel, to the sudden consternation of others, especially those in or near the bomb room.
To the right of the co-pilot's seat was the bomb sight controller. This was yet another wondrous example of analogue ingenuity. The bomb sight itself was mounted forward in the bow compartment, looking though a thick transparency just below the front gun turret. It was an angle rate device. From the ballistics of the store to be dropped and the height and speed of the drop, one could calculate how far before the target to make the release.
Working out that point in space was one thing, but to know when one had arrived at it was quite another. The bomb sight had a transparent barrel on the surface of which were etched fine black lines in a gentle spiral. The axis of the barrel was aligned fore-and-aft. When the barrel rotated the lines could be seen against the background, but because of the rotating spiral they appeared to be moving steadily rearward. Now, as anyone knows who has watched roadside poles from a moving car, when the pole is well ahead and the angle of sight is oblique, the pole appears to be moving slowly. It picks up "speed" as it approaches until it zips past and is history.
The same principle applied with the bomb sight. If the moving graticule was adjusted according to the calculated conditions of height and speed over the ground, there would be a point at which its apparent speed and the speed of passage of the target as viewed through it would coincide. That would be the release point, and the co-pilot wound in the parameters to set the graticule speed for the bomb aimer. Great in theory; somewhat more problematical in reality.
The engine controls too were unusual. Wires and pulleys were not for the throttle levers or the propeller pitch controls in the Sunderland. They worked by hydraulic action known as the exactor system, whereby there was a pipe full of fluid connecting each throttle or pitch actuator in the pedestal with the relevant receptor on each engine. Movement of a small piston at the cockpit end caused a corresponding movement by a similar piston at the other end. Very clever; but in the case of the throttles, unless one had arms the length of the average gorilla's, one could not move the cockpit levers to full power and have the seat shoulder harness done up at the same time. Man-machine interfacing was not at its best in the Sunderland.
So we move from the bridge down the steps to the bow. Here one had to bend double, but in this compartment there were many purposeful things. A hand-held fog bell, an anchor, the anchor winch - and an axe, allegedly there to cut through the anchor chain in an emergency. How it might be swung effectively in the confined space was never explained; and those who had tried found also that its blade was no match for the steel of the chain. It simply bounced off, not without risk to the shins of its wielder as it did so.
There was also a bollard for mooring. It was stowable, under the front turret. The turret itself was retractable, by hand winch mounted in the roof. Wound back, this enabled the bowman to mount the bollard and to stand in the bow to catch the buoy or release from it.
Just aft of the bow compartment, on the starboard side and down a step, was the toilet. This had a header tank which was filled with sea water. In the air the contents of the bowl were simply discharged overboard by hand pump, raw into the environment without benefit of millepore filters or other treatment. Needless to say there were rules about where it was used, and certainly not until the machine was in airborne motion as it were. Furthermore, once airborne there was no means of re-charging the tank with water, so careful economy was the rule of the day.
PART 2 NEXT
Flying Sunderland "boats" on maritime patrol seemed always to mean getting up at an unsociable hour. Perhaps because they cruised so leisurely, it was necessary to take off at the crack of dawn, or earlier, in order to be sure of doing anything very much before nightfall.
Having arisen however reluctantly, the immediate purpose is to satisfy the engrossing hunger that is a part of such small hours. A sympathetic system makes available a breakfast of monumental proportions at the Combined Mess.
Then to the squadron for briefing. Close-in, lights on the hard-standing reflect on the water in the pre-dawn stillness. Farther out, the water ripples in light airs coming down the channel. Ground crew are busy. Marine Section tenders fuss around the jetty, and ruffle the surface between shore and aircraft. The control launch is readying to put out.
In the operations room the navigators plot the patrol on their charts. The weather will be mostly broken cloud, some showers, wind on average 350 degrees at 15 knots, except for a front lying across the route about five hours out. They hunch over their computers - not the modern digital variety, but a device with a circular slide rule on one side and a wind-and-course triangulation gizmo on the other.
The flight engineers worry about fuel load and all-up weight; and the signallers about frequencies, Morse keys and code books. The pilots worry everybody including themselves, quiz the ground engineers, and eventually condescend to sign the maintenance release and the flight authorization.
It is not yet light as they go to the jetty, to the barge, and to the aircraft. The captain asks who has the flight rations - meaning what is in them? It will, after all, be a flight of more than twelve hours and he needs to savour the possibilities in advance.
The great white aircraft looms up in the half-light. “Watch it” calls the captain to the coxswain as the barge noses under the overhang of the wing, in his early morning irritation making an attempt to stamp his authority where it does not belong. The marine diesel bubbles briefly under power as the boat is brought to a halt with a scritch of rubber when the gunwale fender kisses the side of the aircraft. The mooring buoy streams out ahead, though the aircraft lies awkwardly askew under the competing influences of the tide and a now-rising breeze.
Aboard, the aircraft stinks. It has been tightly closed up overnight. It is redolent of salt water, mildew, verdigris, oil, fuel, sweat, old cooking and a primordial blend of liquids slopping in the bilges. Hatches quickly swing open to admit fresh air.
The navigators lug to their station on the upper deck their heavy bags of charts, logs, sextants, pencil boxes, protractors, dividers and other symbols of their art. The signallers and engineers repair variously to their stations and to other parts of the hull on their appointed pre-flight duties. One goes to the galley on the lower deck.
The Sunderland was always in two minds whether to be ship or aircraft. In New Zealand service as the Mark V, it was designed and built by a shipyard, Short Brothers and Harland of Belfast. Of semi-monocoque construciton it was a four-engined high-winged monoplane, so it was said. But it had a bridge, a wardroom, a galley, a keelson, chines, both a nautical and an aeronautical almanac (and nautical and aeronautical charts), a fog bell, an anchor and a leadline.
The galley was a grand misnomer for a cramped space where one cooked upon two Primus stoves on a bench with a sink. Hard beside was a ladder leading to the upper deck. This and the other compartments ran full across the width of the hull.
The galley had a sizeable hatch either side. Beneath each was a large container for the sea drogues. The aircraft had no sea rudder nor water brake. On the sea it was steered and the speed was controlled by a combination of asymmetric power from the engines, the air flaps, the ailerons, the air rudder, and the drogues which were launched by hand from the galley hatches. These were windsock-shaped canvas sleeves with a thin wire hawser cleated to a frame on the bulkhead. Once deployed, the force of the water flow usually meant they could not be recovered until the mooring was complete - and even then with difficulty in a strong-flowing tide. They had a spill rope attached to their tail so they might be collapsed again if need be, but it seldom worked reliably. It was better to assume that once deployed they stayed deployed, which normally meant the pilots had to call the one-shot moment with care.
Next forward of the galley was the wardroom; also a grander name than the compartment deserved. There was a bunk down each side and a fixed table with fold-down leaves in between. Naturally enough, even with the leaves propped open the surface remained out of reach of a diner of normal proportions seated on the bunks; and the height was as badly matched. To give a feeling of home, however, the table was finished in a tasteful light green. The deck was bare dural, though with worn remnants of green paint, strengthened underneath by stringers, their skeleton outline emphasised by depressions and bruises in the much-worked surface between. The walls were bare dural as well, being the thin outside skin of the aircraft. No padding, no lining, no gestures to livability; just the skin marked out by vertical constructional ribs and horizontal longerons, punctuated by tastefully rounded portholes. The wardroom became an action station on operations, for it housed the sonobuoy acoustic receiver.
Throughout the lower deck and beneath the decking, a bulkhead sealed each compartment from its neighbours. Above the decking, doorways between were fitted with swash doors extending the watertight isolation of compartment from compartment to about three feet above the deck. These could be opened but were normally dogged shut. To pass through one could open the swash doors after wrestling with the dogs or simply step over them, the latter for preference, though at some risk to the person, especially those shorter in stature. The lower deck panels had ring latches so they could be lifted to get at the bilges and dark spaces beneath, should the need arise.
Aft of the galley was the bomb room. This contained marvels of expedient engineering. In a flying boat, breaching the planing hull to provide such as bomb or torpedo doors is a design challenge. Here, the designers had chosen not to tackle the challenge head-on, but to avoid it. The weapons were carried wholly inside the hull. Bomb racks were mounted along the lower line of the wing two decks up. To load or reload in flight there was a winch, hand operated by chain, to lift the ordnance from the floor to hook up to the racks.
So far so good. There remained the problem of getting the racks outside and clear of the airframe so the weapons could be dropped. The design engineer had provided an ingenious system in which, one supposes, as each problem was solved another arose to be solved in its own way. Sequential engineering.
The racks ran out on rails beneath the wings, powered by electric winch (or if that failed, by a crank wound by hand). When the racks were retracted inside, flexible strips were drawn over the rails set into the under-surface of the wing so the airflow would remain undisturbed by the discontinuity.
But with the racks inside and needing to get outside, the fuselage walls were in the way. Very well; put a door each side. These were not ordinary doors, however. They could not be hinged outward for reasons of slipstream, nor inward for reasons of space. So they slid vertically in a frame, from high up under the wing root where the bomb racks were poised on their rails.
It was necessary to seal around these doors, otherwise the spray would come in during takeoff and landing. Therefore the mounting frames were designed to move bodily inward to break the seals, whereupon the doors could drop vertically downwards along guides in the frames. The release latch to effect this was operated electrically from the cockpit, with a local manual release for emergencies. The tensioners that sprung the frames clear, breaking the seal and giving the doors room to drop, were none other than stout rubber bungees - and the doors were similarly cushioned as they fell to the limit of their travel. The original bungee jump - eat your heart out A.J. Hackett!
Aft again was another compartment with bunks, graciously called the after crew compartment. From there the floor sloped up toward the tail and the rear gun turret, with a chute nearby for dropping flares and smoke markers. This, too, had an example of thoughtful engineering design, practical though looking slightly home-made. Should a flare become jammed in the chute and burn, the results might be serious. The safety device was a broomstick, conveniently clipped to the wall, which one could use to persuade the errant flare to depart.
Nearby there was another monument to the nature of this beast. On the starboard side near the rear external door there was a box. In it was an array of rubber stoppers in various sizes with which to plug leaks in the planing hull. Likewise it housed a number of heavy coir mats. And there were generous wads of ordinary plasticine for the same purpose (but not in bright kindergarten colours, only regulation dingy grey-green).
Turning and moving forward again there was a step to the upper level via a hinged bridge between fixed platforms on each side. These were the waist gunner's positions. Wide hatches opened to enable a hefty point-five Browning machine gun to be mounted on a pintle each side, the barrel sticking out into the airflow. It was a free-firing weapon; if the gunner forgot to screw in the safety stop he was quite likely to shoot up the wing float in the heat of the moment. It did happen.
Moving on forward we mount up a ramp and through the central box wing structure to a tiny door at the back of the crew deck. On this ramp, to the right, was a significant device. The Sunderland in RNZAF service was equipped with the ASV Mark 6C maritime radar. But with gun turrets at the nose and tail of the fuselage, and the planing hull underneath, there was no place for the antennae but the wingtips. A radome blister was therefore attached under each. That presented a further difficulty. The radar had to look down to the sea, but from each wingtip the hang of the fuselage blocked out a goodly part of the sweep. The solution was a hefty waveguide switch which transferred the radar energy from one wing to the other at the appropriate moment each scan. With the radar running it did this with a noisy clack-clack, at least loud enough to be audible above the roar of the engines, unattenuated by the thin aircraft skin.
Moving forward again (and being careful not to fall through the open hatch into the galley below) there was the engineer's desk on the right and, stepped just forward of the front wing spar, the signaller's desk on the left. The engineer faced aft watching his panel with the engine health gauges and all of the fuel gauges and supply cocks. The signaller faced forward, presiding over an array of heavy black boxes by Marconi, with mysterious dials and knobs and, under the covers, tuning devices curiously named pecking motors. Fixed to the desk was a Morse key. Though the aircraft used HF voice modes extensively, Morse procedures were a prominent and necessary part of communications. Some signaller aficionados disdained the supplied key, and fixed their own personal "bug" in its place. This was a clever semi-automated two-way switch operated between forefinger and thumb. When the lever was moved one way a weighted spring trembler produced a stream of dots, whilst for a dash the lever was moved the other way. It provided for greater Morse speed, though in turbulent conditions it could be more difficult to use without stammer than the standard key.
Above and centre was the astrodome. In the air this was a good lookout point besides being the mount for the navigational sextant. On the water the hatch and dome could be removed for egress to the top of the fuselage and the wings. At the rear edge of the hatchway was the engine starting panel, complete with priming pumps, selectors and starting booster controls. However, unless one was an eight-foot giant one could not see out of the dome or the hatch from the flight deck. There was provided, therefore, a stowable platform to stand on.
Moving forward, the navigator was on the right and the tactical navigation table on the left. The latter had a ground position indicator, a machine which projected a crossed arrow onto a chart from above, purporting to represent the aircraft's position during ASW manoeuvres. It was intended for short-range tactical use only, being an analogue device of bell cranks and pulleys which was reliable for all of a minute or so after it was set up.
On the right was the radar tent, just behind the co-pilot's seat. It had black curtains all round, which had to be closed in daylight if the operator was to make much of the screen. It was also a nice place for a kip.
Forward yet again to the pilots' seats; or the "bridge", since this was a boat. Instruments on the panel, throttles and other engine controls in between the seats, flying trims overhead, and switches placed at random all around. Between the seats and just aft of the throttle pedestal, another opening led below to the bow compartment.
On the deck to the left of the captain's seat was the standby P-type magnetic compass; and near it the bomb door and rack actuation switch. If sufficiently ham-footed it was possible to kick this switch into action with the left heel, to the sudden consternation of others, especially those in or near the bomb room.
To the right of the co-pilot's seat was the bomb sight controller. This was yet another wondrous example of analogue ingenuity. The bomb sight itself was mounted forward in the bow compartment, looking though a thick transparency just below the front gun turret. It was an angle rate device. From the ballistics of the store to be dropped and the height and speed of the drop, one could calculate how far before the target to make the release.
Working out that point in space was one thing, but to know when one had arrived at it was quite another. The bomb sight had a transparent barrel on the surface of which were etched fine black lines in a gentle spiral. The axis of the barrel was aligned fore-and-aft. When the barrel rotated the lines could be seen against the background, but because of the rotating spiral they appeared to be moving steadily rearward. Now, as anyone knows who has watched roadside poles from a moving car, when the pole is well ahead and the angle of sight is oblique, the pole appears to be moving slowly. It picks up "speed" as it approaches until it zips past and is history.
The same principle applied with the bomb sight. If the moving graticule was adjusted according to the calculated conditions of height and speed over the ground, there would be a point at which its apparent speed and the speed of passage of the target as viewed through it would coincide. That would be the release point, and the co-pilot wound in the parameters to set the graticule speed for the bomb aimer. Great in theory; somewhat more problematical in reality.
The engine controls too were unusual. Wires and pulleys were not for the throttle levers or the propeller pitch controls in the Sunderland. They worked by hydraulic action known as the exactor system, whereby there was a pipe full of fluid connecting each throttle or pitch actuator in the pedestal with the relevant receptor on each engine. Movement of a small piston at the cockpit end caused a corresponding movement by a similar piston at the other end. Very clever; but in the case of the throttles, unless one had arms the length of the average gorilla's, one could not move the cockpit levers to full power and have the seat shoulder harness done up at the same time. Man-machine interfacing was not at its best in the Sunderland.
So we move from the bridge down the steps to the bow. Here one had to bend double, but in this compartment there were many purposeful things. A hand-held fog bell, an anchor, the anchor winch - and an axe, allegedly there to cut through the anchor chain in an emergency. How it might be swung effectively in the confined space was never explained; and those who had tried found also that its blade was no match for the steel of the chain. It simply bounced off, not without risk to the shins of its wielder as it did so.
There was also a bollard for mooring. It was stowable, under the front turret. The turret itself was retractable, by hand winch mounted in the roof. Wound back, this enabled the bowman to mount the bollard and to stand in the bow to catch the buoy or release from it.
Just aft of the bow compartment, on the starboard side and down a step, was the toilet. This had a header tank which was filled with sea water. In the air the contents of the bowl were simply discharged overboard by hand pump, raw into the environment without benefit of millepore filters or other treatment. Needless to say there were rules about where it was used, and certainly not until the machine was in airborne motion as it were. Furthermore, once airborne there was no means of re-charging the tank with water, so careful economy was the rule of the day.
PART 2 NEXT