Spearpoint pumps on the Peninsula

It was in 1979 when my family and I first arrived on the beautiful Peninsula and rented a quiet property in Umina Beach.

Two years later I found a small fibro and tin roof place in Woy Woy that I could afford.

There I met and became mates with my back-fence neighbour who was a little outspoken about a certain subject.

"You need a Billabong, mate," he said (whatever that was).

He was so persuasive and knew all types of people and convinced me that with his help and a mere $40, he had a second-hand piston pump and a spearpoint lined up.

Not only that but he could help me install the spear and see that it was connected properly.

Another $40 spent at the Packing House and I had a working pump, pipe to front and back yards and two taps; it was at this time I became hooked.

It was a while ago but still seems fresh in my mind and, in 1985, I bought into a pump and irrigation business.

My then business partner became the first person that I am aware of to make a PVC composite spearpoint with 316 stainless steel, 50 mesh and held on to a hole saw-drilled 32mm PVC pipe with rivets and waterproof tape.

There were a few teething problems with the original and we quickly found out a lot about electrolysis.

My father required some underground water and I, being a bit on the conservative side, put two of my handmade spears and connected them to a 750 watt pump coupled to an 1100 watt motor.

With only the replacement of a poly checkvalve, this unit still runs beautifully to this day.

My business partner and I parted company and the manufacture of PVC spearpoints became my domain; rivets were now monel, tape replaced with heatshrink and never more to place a check valve on top of the spear but nearer to ground level.

I have probably made around 1000 of these in total as even when I temporarily moved bush, I would periodically post the odd consignment to my good friend back on the Coast.

I am not certain when the first piston pumps came to the Peninsula but it had to be in the 1940s and they were the mainstay of users for a very long time.

As the power grid in those days was apparently strained to capacity, these pumps were probably the only type which could have been legally used successfully.

Due to the fact they could be coupled to a quarter horsepower, 1440 RPM electric motor, they were certainly the main method of obtaining much-needed underground water.

Many of these electric motors, under close scrutiny, might be found to have a number four punched over the top of the number three on the compliance tag; shock.

Being positive-displacement meant they were quite capable of using half inch hose, as the original pumps, I believe, were matched to the practical limits of this size hose.

If the hose was "jumping" during operation, you needed to put on another hose.

They came with various brand names and in quite a few different outputs: 22 Litre; 30 Litre; and then later the 28 Litre (which ran at faster speeds).

There was even a small aluminium Chinese pump that made it here but they were quite rare (and beautifully made too).

The piston pump's reign became threatened when drought set in during the late 1970s and as demand outstripped supply, the jet centrifugal seriously put its foot in the door.

It marked the beginning of the end for the piston pump as, with the price of manufacture now making them very expensive indeed, jet centrifugal pumps became a real force to contend with.

The piston pump really only held on into, I think, the early- to mid-1990s, not a bad run though.

As the name implies, it is a centrifugal pump which contains a jet.

There were several advantages of this type of pump compared to a normal centrifugal pump, such as better priming from a depth, a pressure gradient which made automatic operation more practical and a better output at higher pressures.

On the down side though, for people who were used to piston pumps and still locked in to using half inch hose, they seemed to perform poorly by comparison.

A jet pump will provide a much higher flow rate at lower pressure at the pump than it will at higher pressure.

Thus using half-inch hose forces the pump to work at a higher pressure to overcome the losses in the hose and this effectively strangles its output.

The solution is to increase hose size and/or reduce hose length.

A case in point is someone who used a jet centrifugal and had been running a single sprinkler for about eight years.

I cut his 18-metre, half-inch hose in half, made up the difference with 18mm hose, added fittings and another sprinkler of the same type and, hey presto, he now had twice as much output.

When he questioned me about the sudden improvement, he could hardly believe the difference and regretted running his pump for twice as long and using twice as much electricity as he needed to, over such a long period of time.

Thousands of this model pump were sold by the old Umina Pump Service over a period of several years.

The owner produced the Labyrinth or Poly Spear.

The jet centrifugal is here to stay and improvements in pressure control design make them very reliable and almost foolproof today.

The original metal spears were, as the name implied, equipped with a spear-tip and these would normally be belted into the water table by various means.

These were the mainstay for many years and their contribution in providing underground water cannot be emphasised enough.

Coupled to the ubiquitous piston pump they were a major force for more than a generation (or two).

The longevity of these types of spear points was considered as not very impressive.

Having been manufactured with holes drilled through galvanised steel and welding done to add the protection for the stainless steel (or bronze) mesh, (no re-galvanising), the attraction to the bare steel by minerals within the water made them block up. It can best be described as either coral-like in appearance or like a mushroom which grew through the screen from the bare steel.

As the performance of the pumping system decreased, a lift-and-clean was necessary and was required sometimes as often as every 18 months.

This entailed hauling the galvanised steel pipe up which was achieved by many and varied lifting techniques.

My preference was to dig down alongside with a sand auger until the whole pipe section could be rotated in the wet sand and then lifted out.

You would now have to undo the spear and acid treat it to remove the build-up.

After a thorough flushing the whole lot was re-installed: thump, thump, thump.

With the increase in manufacturing costs, together with the higher flow rate required of more modern pumps, the advent of alternatives spear points as well as the costs involved in maintenance; the days became numbered for this very important part of pumping history.

In the late 1970s, a remarkable man from Umina Beach hit on the idea to build possibly the first-ever, non-metal spear point.

I have never heard it named (apart from poly spear) but I have taken to calling it the Labyrinth Spear.

The makeup of this unique spear point hinges on the close fit between one-and-a-half inch Rural 50B which is a very tight fit over one-and-a-quarter inch Rural 50B poly pipe.

Now take a fine hacksaw blade, hit gently with a hammer to remove the wave and prepare your two different sizes of pipe.

Once these were anchored in position, cuts were made through both pipes at one inch intervals; this was done on four sides.

Having made the appropriate number of cuts in each vertical row, the two pipes were then stepped a half inch vertically apart and locked in place; water needed to go through the fine cuts, down between the pipes and enter the fine cuts of the inner pipe then to be drawn up to the pump.

Materials, by comparison, with steel spear points, were fairly cheap and their capacity was more than reasonable.

On a less promising note, this type of spear would sometimes bleed fine sand.

The surprising side benefit of this type of spear was in the way these Labyrinth spear points were actually placed into position.

You couldn't thump them in so what was in effect a mining technique called "bailing" was employed.

A PVC tube was pushed down into the water table once the sand auger had stopped picking up.

A cross between a yabby pump and a windmill pump was then employed to evacuate the PVC tube which was moved further into the water table.

Once this was evacuated of wet sand to the chosen depth, the spear point, plus check valve and poly pipe tail were quickly inserted and the casing removed.

I believe some still survive even 30-odd years later.

Once this type of spear point had been brought into creation, all other types of spear points, in my opinion, became obsolete.

Material costs, tools and techniques were such that they could be made by individuals and thus future-proofed against any manufacturing short-falls.

Flow rates went through the roof with properly designed spear points and their longevity is such that my humble examples some 30-odd years ago are still functioning as good as the day they were installed.

Using the techniques described it became a relatively straightforward exercise to install composite PVC and stainless steel mesh spearpoints.

Another technique which has been developed successfully is that of "jetting".

This technique is no less successful to that of the "bailing" technique.

It is my preference, and has been for many years, to have good quality check valves used and installed at ground level.

Some may feel that this is not the way to go, but have you ever filled a bottle with water and placed the neck under water in the sink?

Simple physics would show that it is atmospheric pressure that holds the water in the bottle. The seal on the check valve is held closed when not in use by atmospheric pressure plus any residual pressure form the pump system.

My belief is that in the unlikely event that a check valve leak occurs, it can be repaired without lifting the spear point.

In its most recent incarnation, I have chosen to increase the surface area, utilise stainless steel blind closed-end rivets and with the sealing of the mesh achieved by rebating both the end cap and coupling which fit over the mesh ends (no more heat shrink).

Other good examples are out there.

Letter, 30 Jan 2017

Larry Patterson, Umina