The Paramount Cub portable centrifugal pump was manufactured by Pumps & Power in Canada, and patented in 1941. What year it was adopted by the NZ Forest Service is unknown. The two-stroke, twin cylinder, horizontally-opposed engine and pump were assembled as one unit on a stainless steel base designed for pack-board transport. Net weight was 34 kg. It had a detched fuel tank holding 22.5 litres of 8:1 mix two-stroke fuel. As the photo shows, the Forest Service modified the pump so that it had an integral fuel tank. Hose power was quoted at 12 to 15, maximum of 4500 rpm. The pump was multi-stage with three impellers, plus an additional impeller to make it self-priming. Casing and impellers were made of high tensile pressure-tight aluminium. Its performance was:
The Forest Service started rural fire competitions with this pump in the 1950s. It was known to be difficult to start - DOC's Lindsay Golding said it was referred to as 'The Beast', and it paid to have a pocketful of spare spark plugs - not surprising given that fuel mix ratio!
The Wajax pump was originally manufactured by Wajax Manufacturing Ltd of Montreal, Canada. It was adopted by all Canadian Provincial Governments in 1955, and the NZ Forest Service followed suit in 1956. The Service had ben looking for a replacement for the Paramount Cub, and had trialled some dozen IEL pumps before this. Remarkably, the Wajax is still the mainstay high pressure/low volume pump for rural firefighting in NZ over 50 years later; in 1995, the RFAs had 936 of them2. The four-impeller pump unit (designated 12-16) appears little changed, and it is the motors that have given rise to the different versions. However, Wajax sold off its fire business, and the pumps are now manufactured by Wildfire Equipment, still in Canada.
The original Mk I was produced with a twin cylinder, 9 hp air-cooled Kiekhaeffer-Mercury motor that had also been used for early (two-man) chainsaws - see opposite. There are a few of them still around and, with its low profile and efficient operation, it remained much preferred to successive versions by many of the older firefighters. It lacked silencers and was very noisey, but was comparatively light and had an integral fuel tank. Total weight was 26.4 kg (engine 19.5, pump 6.8 kg). Unfortunately, Wajax were unable to continue sourcing that motor in 1960, and produced a Mark II in 1961. The Mark II was not imported into NZ, and we continued to receive a few Mark I's after that year. The Mark II had a single cyliner Rotax engine which was of Austrian design. In Canada, it was used to power the original Skid-Doo snow mobile. In 1963, this engine was modified to fit a diaphragm carburettor, Mark IIM, eliminating the need to raise the integral fuel tank above the motor.
Mark III Wajaxes were launched in 1965, and these were imported into NZ. This was also based on the Rotax motor, producing a similar output to the Mark I, but at 31.8 kg was heavier. Vibration and unrelaible operation prompted the NZ Forest Service to look for an alternative motor. There was a comparatively brief period with a Sachs-Wankel twin-cylinder rotary engine in the 1970's. This motor ran on a 50:1 petrol mix, producing 9.3 hp, and the pump weighed in at 36 kg. The muffler on this motor got extremely hot, and would glow red in the dark. Refuelling could be hazardous! However, other than some burning out some readily-replaceable wiring, damage was minimal should this happen.
The German firm that produced the Mark IV motor could not compete with Japanese models, and ceased production of the rotary engine. In 1982, the Forest Service supplied a pump unit to agents Youngman Richardson & Co., and they manufactured an adapter plate to couple a single-cylinder Robin EC17D motor. The test performance was judged outstanding, and the motor was adopted as the standard engine to power the Mark V Wajax pump in NZ. Robin engines were specifically designed in Japan as a high performance motor to power firefighting pumps, notably the Rabbits. Over the years, the Robin EC17DFF variant of the engine was used for the Mark V. The combined weight was 33 kg, but pumping performance was improved. This engine produces 10 hp (7.5 kW) at a maximum governed rate of 6500 rpm, giving a maximum pump pressure of about 2450 kPa.
Late in the 2000's, the Robin motors became unavailable. There has been a return to purchasing what are essentially the Mark III Wajax pumps, still made in Canada. There have been some refinements to the design . Once of these was a change in suspension to the frame; the other saw the removal of the integral fuel tank because of health and safety considerations, with a detached tank used instead. As a consequence, the Mark 3 pump weight is now 26.3 kg. The 185 cc Rotax motor produces 10 hp power (7.5 kW), and the maximum pump pressure is 2620 kPa. The original decompression valve, included to make for easier starting, seems now to be an optional extra.
The Wajax BB-4 pump was introduced to NZ in the 2000's as the main deck pump on the NRFA-specified Isuzu rural fire trucks. This variant couples a 23 hp (17.2 kW) Briggs and Stratton Vanguard engine via a belt to the standard 12-16 Wajax pump. The higher power of the four stroke, air-cooled, twin cylinder motor boosts maximum water pressure to 2930 Kpa and freeflow to 397 lpm. At 72 kg weight, the BB-4 is not designed to be backpack portable, but its cradle is interchangeable with the Mark III. And it's the only version with a pressure gauge!
* = has detached fuel tank. All engines are petrol.
During WWII, the Government followed the British example and set up a 3000-strong Emergency Fire Service to augment brigades in the major cities1. They were equipped with 1800 lpm trailer pumps, driven by a V8 Ford Mercury car motor. The Colonial Motor company produced over 1700 of these during the period between 1941 and 1945. The December 2011 K1 magazine provided a history of their development. Many were shipped overseas, but around 160 were kept in NZ. 29 heavier Dennis trailer pumps were imported from Britain. After the war, many of the trailer pumps were allocated on permanent loan to volunteer fire brigades. Some rural units aquired these, and use persisted through to about the mid-1980s. Gwynne trailer pumps, 1140 lpm, based on 4 cylinder engines, were in the 1950s. On nationalisation in 1976, the NZ Fire Service still had 105 trailer pumps. Trailer pumps were popular and the UFBA ran competition events based on them.
In 1995, it was estimated that RFAs held 486 volume pumps2. The standard volume portable pump for the Forest Service was the self-priming Aqualite, which is still in use by DOC and other organisations. It is a simple, cheap, low pressure/medium volume pump suitable for filling purposes (1,200 lpm freeflow), but is inadequate as a high performance base pump for hose operations. In the latter function, the distinction between rural and urban firefighting requirements blurs, and the same portable pumps have been used by both services, although the NZFS generally preferred higher volumes. They tend to have 100 mm screw inlets, with two 70 mm instantaneous couplings as outlets, and are water-cooled. A common one used by brigades from the 1960s was the four-man Featherweight pump, powered by a 4 cylinder Coventry Climax car engine. It was used in UFBA fire competitions. Twin cylinder two-stroke Japanese portable pumps such as Rabbit and Tohatsu were popular as lighter and cheaper alternatives from the 1960s. With the nationalisation opf the NZFS in 1976, standardisation on pumps was inevitable. However, the rural sector remained free for choice, and outside of the Forest service, RFA's have used a large range of pumps, including hand-me-downs from the NZFS. The following table summarises some of them, including the modern ones still in use. The Firemaster 22 and Millennium 22 are essentially the same pump, just rebranded, and are made by Vortex Holdings in Hawkes Bay. The Wajax BB-4 is not a volume pump, and is included for reference only.
Performance figures may not be strictly comparable as they depend on the suction lift at which the measurements were made.