Starting from the very basic principles our development team came up with a system that circumvents all the inefficiencies of the propeller.

History

Some 220 years after the invention of the propeller the efficiency improvements to the original design have been minimal, only a few percent in total.

So, it was time to completely re-evaluate methods of creating thrust in water with the view to improve efficiency as by now it was patently obvious that the propeller was archaic.

Our objective was to improve on the accepted Industry Standard of around 4 kg/HP* of thrust for an unshrouded propeller.

*QM2 3.87 kg/HP
*Emma Maersk 4.10 kg/HP
*Volvo’s IPS drive 3.84 kg/HP

The inventors of the technology, protected through a Provisional Patent Application (namely TGPS marine drive), did just that. Starting from the very basic principles they came up with a system that circumvents all the inefficiencies of the propeller.

The development team then took this system and, with the help of the inventors, streamlined it over a 5 year period to finally end up with a fully-scalable prototype that could be tank tested to demonstrate the remarkable efficiencies offered.

Development

In developing their concept, the development team disregarded all previous technology and set about focusing on the most efficient and effective way, any way, to produce thrust. What they came up with is a completely new, revolutionary way to convert power (Watts of energy in) to thrust (Watts of energy out).

Initially, it was decided to do a static test in a swimming pool using a 10 hp, 4 pole, 3 phase electric motor connected to the new “thruster” via a motor controller. The motor controller allowed for all input and output values to be determined, as well as controlling speed variations.

Static test results revealed that performance efficiency (i.e. Watts in to Watts out) was 88.79%. In other words, the system only lost 11.21% of the input energy while delivering an impressive thrust of water.

Methodology

The prototype designed and constructed for tank testing comprised the following components:

  • Main power delivered in 3 phase, 415 volts, 50 Hz from the mains supply to a Varcon Multi-control NXL model motor controller. The motor controller not only controlled the power and frequency to the prototype, allowing us to vary the motor speed, but also allowed us to read off relevant input/output data very accurately to ascertain efficiency.
  • From the motor controller, power was delivered to a CMG 4 pole, 3 phase, 7.5 kW electric motor. This motor was directly coupled via a shaft to our new TGPS marine propulsion device prototype.
  • A digital speed log was located in the device’s water exit. This fed water velocity readings back to a digital readout display.
  • The whole mechanism was gimballed so that as water thrust was achieved out of our propulsion devise, equal pressure was applied to a calibrated PT Load Cell that measured kilograms digitally, thus allowing a mechanical as well as a mathematical proof of principal.

Tank Testing Results

Tests were conducted for various frequencies directly related to the motors rpm and results are shown below:

Hz 50 40 30 20
RPM 1435 1158 876 580
Amps 23.3 15 10.1 7.7
Volts 415 332 249 167
Motor Efficiency 78% 87% 76% 46%
HP 15.05 8.35 3.11 0.55
Load Cell 159.3 111.3 65 28.3
Thrust kg/hp 8.52 12.51 25.45 30.24

Notice the very interesting trend: as the motor’s rpm reduces to 580 the Thrust in kg/HP increases significantly!

The apparatus used in the testing could not go below 20 Hz (580 rpm). However, from mathematical modelling (which replicates the above recorded test results) the optimum PRACTICAL speed is between 100 and 200 rpm for big ships.

It is intended to prove this optimum practical speed on the TGPS demonstration ship at 140 rpm, as this matches the desired performance.

The above collected data and calculations clearly demonstrate that, even at 580 rpm, 30.24 kg/HP of thrust is achieved.

To put this into perspective, consider a range of thrust kg/HP for existing, well known ships and pleasure craft propeller propulsion:

QM2 3.87 kg/HP
Emma Maersk 4.10 kg/HP
Volvo’s IPS drive 3.84 kg/HP

The ramifications of TGPS and research data collated are obvious. With fully-scalable drives, and demonstrated efficiencies, the horsepower requirements, fuel usage and emissions for all vessels may be significantly reduced, while maintaining optimal performance.

Consequently, fuel usage (and emissions) may be dramatically reduced.

Scalability

After designing a program within which pump requirements are input to automatically generate dimensions and design criteria, the construction of a full size pump was the next step in demonstrating that the system can be built to any size practical to existing hardware.

To that end, access to a local farm included the use of a large tractor, a large dam and convenient workshop facilities. A system was built to match the output pump to the maximum capacity of the IH 766 tractor and PTO drive.

As demonstrated from previous testing, a slower rpm is more efficient, so a 5:1 gearbox coupled to the tractor’s 540 rpm (max) PTO drive was used to generate a maximum pump speed of 108 rpm.

Test results performed EXACTLY to the program’s design criteria, proving conclusively that the system is fully scalable. This pump delivered extraordinary results:

  • 254,600 tons or 254.6 megalitres/day from just 78 hp.
  • 2.947 cu metres/second
  • 24.57 kg/hp Thrust, some 6.14 times the industry standard of 4 kg/hp.

The large pump designed for the scalability test proved that the system can not only replace propellers in large ships, but also move massive amounts of water in irrigation systems, de-water flooded open cut coal mines or even pump sewerage systems for cities and towns.