Props-R-Us

Barry Wiseman | VOLUME 22, ISSUE 3
Cavitation trials.
Luxury yachts and competition sports fishing boats are knocking at the door of a Western Australian engineering company, demanding their high-tech propellers.

Imagine this. One of your two engines is losing power. There’s a five per cent loss somewhere and a difference of 70rpm between the gauges of both motors, translating to a speed reduction of one-and-a-half knots. After thorough investigations, naval architects and engineers eventually trace it back to a faulty fuel injector on one of the 20 cylinders on board.

The diagnosis proved correct, the injector was replaced and the vessel returned to the manufacturer’s performance claims, much to the customer’s satisfaction.

This is a real life story and highlights the dramatic achievements of the VEEM Engineering Group, which is pioneering new propeller designs to the world.

A dozen or more of the world’s leading boat manufacturers are now fitting the company’s custom-designed propellers to their vessels. They include Australia’s Riviera, and US-manufactured Viking Yachts, Cabo Yachts, SeaRay, Hatteras Yachts, Spencer Yachts, Buddy Davis, Blackwell Boats, Scarborough Yachts, Merritt Yachts, Trinity Yachts and Christensen Yachts.

The name VEEM comes from the initials of the Western Australian group’s founders, Voyka and Elizabeth Else Miocevich.

Director of Marine Propulsion, Brad Miocevich, likes to refer to their product as “Splash and Forget” – saving the manufacturer thousands of dollars in man-hours and fuel.

“Once the boat is launched, they know it will perform as specified. There’s no need to conduct repeated sea trials, testing various propellers to achieve maximum performance,” Brad explained as we sat in the boardroom of the company’s headquarters in the Perth suburb of Canning Vale.

VEEM has been building propellers using traditional foundry and hands-on methods since 1956 and has a database of thousands of vessels, which it uses to constantly verify and fine-tune its designs.

Miocevich explained that a lot of boat manufacturers around the globe experienced issues with burning on the root area of the propeller blades due to cavitation bubbles collapsing onto the surface of the propeller. Variability in the shape of each propeller would also result in different engine revolutions, he said.

The performance of boats would vary and manufacturers were faced with a dilemma: was it the hull resistance; the engines; or the propellers? One thing was for sure, they faced at least one, and most times several prop changes, which involved lifting the vessel out of the water. Plus, there were the man-hours in changing over to another propeller, and more burning up of expensive fuel conducting further sea trials.

And matching twin propellers was almost impossible. Traditionally, the polished finish on the blade surface was done by hand and would vary, with even minute differences affecting engine and boat performance.

ROOM FOR IMPROVEMENT

While some companies have been using computer scanning for years, they only measure the pitch face of the prop. Realising there were more features and geometry critical to propeller design and manufacture, especially to suit high performance luxury and sports boats, VEEM decided to search for improvement.

“It’s like concentrating on the underside of an F-18 wing, when the top side of the wing produces all the lift. Propellers are not too different; you need to focus on all aspects,” said Miocevich.

In 2004, the company embarked on an extensive research and development program aimed at producing a better product and, hopefully, gaining a competitive edge in the market place.

It now has a team of 160 naval architects, engineers, computer program designers and foundry and office staff working on its two-hectare site at Canning Vale. The electric powered foundry and workshop occupy 12,000 square metres, comprising the latest robotics machinery to produce a high-tech product. The equipment and know-how developed by VEEM is a closely-guarded secret and the company knows full-well that this is partly what gives it the edge on its competition.

Western Australia is a long way from the major boat-building capitals of the world, not to mention Australia, but the company has developed an advanced internet system whereby clients can order, monitor and interrogate the company’s production schedule so they can have their boats ready for propulsion fit-up within their own delivery deadlines.

In 2006, the group took delivery of its own project vessel: a Viking 64 Sports Fisher, with a sleek Atlantic blue-coloured hull, and powered by twin MTU 16v2000 M93 engines capable of delivering 2400hp at 2450rpm. The vessel is specifically used for validating new propeller designs in the 30- to 50-plus-knot bracket and has attracted much interest over the past couple of years at the Club Marine Mandurah Boat Show south of Perth. It is currently fitted with 39-inch props producing 44-and-a-half knots.

The vessel was deliberately over-powered so the VEEM team could over-power their prototype propellers and find out where they were not performing. They could also use the combination to set standards, and modifications could be made until a required performance level was achieved.

COMPUTER MODELLING

The company starts off with computer modelling of the latest propeller designs using Computational Fluid Dynamics (CFD) software. This gives the designers information as to where the flows, maximum lifts and gains are to be achieved.

A scaled model of the prop is then made and put into a cavitation tunnel for testing. Using the tunnel, the engineers can reduce the atmospheric pressure and get the water to vaporise at room temperature, creating cavitation.

By turning the propeller at different speeds, at the same time controlling the advance of water across the blade, the researchers then induce cavitation and record the performance of propulsion in real time. The issue of shaft angle can also be addressed.

Once the information has been collated, a set of props is cut and trialled on the Viking 64 to check performance attributes, such as manoeuvrability and acceleration.

VEEM claims its propellers are generally one to one-and-a-half knots – and sometimes up to three knots – faster than the opposition.

While it says R&D, advanced designs and performance are important, its major success is in the fact it can guarantee to its OEM (Original Equipment Manufacturers) a highly accurate and stable propeller for every specific boat produced. Once the correct prop has been produced, every one that follows will be exactly the same.

“It costs an awful lot of money to launch a boat, put a set of propellers on it, do a sea trial, which sometimes is quite a distance from the boatyard, collect the data with often two or three people on board, use a thousand litres of fuel, then pull the boat out again and send the props off for fine tuning. They then refit the props and head out for another session and a lot of the builders are doing it three or four times. We are finding this has been the norm in America, here in Australia and in Europe. Manufacturers have accepted it.

“We have now come forward and said if we do the naval architectural work and engineering up front, you give us very accurate data and our team will work with the OEM’s engineers, and we’ll design specific propellers for each model. Once we do that, we produce the propellers using five-axis, high-speed, contouring computer numerical controlled (CNC) machines and every prop is the same. The more accurate the information about the boat from the builder, the better. If we get it right on the first boat, then every boat will get the same delivered thrust for the same given power at the propeller,” Miocevich added.

“A lot of people did scoff at it, but the proof is in the pudding. We get the vessel data, come back to Perth and cut a set of CNC props, fly them to wherever the vessel is in the world, install them on the boat and then they run it. When the propellers do what we said they would do, they start to believe us. We have many companies now enjoying this benefit and many more will want it.”

Each prop is fully machined in the one operation and doing it that way VEEM guarantees a high level of dimensional stability, accuracy and repeatability. The production of a precision designed propeller aids boat builders by significantly reducing at least one of the variables in boat performance.

The VEEM team continues to work with the boat builder to better manage the manufacturing weight-control programs. Consistently accurate propellers also mean the manufacturers of electronically-controlled engines have more confidence in achieving the desired engine speed from launch.

DIAGNOSTIC TOOL

VEEM strictly adheres to the company’s ISO 9001:2000 certified quality control management system and all propellers are engraved so production can be traced. This system enabled engineers to come up with an accurate diagnosis for the cause of lost power in the boat engine mentioned at the beginning of this article. Knowing exactly what prop was fitted and simulating the real time operating events back in the VEEM workshop led to the detection of the faulty injector, which was replaced and the vessel returned to maximum performance.

The company’s foundry division is able to alloy all of its own metals using its National Association of Testing Authorities (NATA) certified laboratory to meet chemical analysis. Most of its props are made from a nickel aluminium bronze alloy, which offers increased strength. Thinner blades can be produced, therefore giving less drag. A team of metallurgists supervises each pour.

The nickel aluminium bronze is well-suited to propeller use, with excellent resistance to corrosion and fatigue. While it is a tough metal, it machines well and the tensile strength allows VEEM to achieve the required thickness.

Chemical analysis of the metal is carried out prior to each pour, so the specialists know exactly what and how much material goes into each propeller.

The company is now studying more advanced bi-metal applications, but these are more expensive and still in the R&D stage. However, with boating manufacturers aiming forever-higher speeds, the need for better materials is inevitable.

VEEM believes the surface finish on a propeller is important and can be improved on beyond normal CNC machining. Its testing has shown that removing the ‘orange peel’-like surface produced by the CNC machining process enhances cavitation control, thus reducing noise and vibration.

The company uses a series of robotic machines to achieve a whole range of highly polished finishes on the blades.

“We believe that at high speeds, the surface finish is critical,” explained Miocevich.

The company is producing around 3000 propellers a year and the propulsion package usually includes all the components in the shaft-line, including the gearbox coupling and the propeller. Also included are the shaft brackets, bearings, seals and rudders. Once the boat builder supplies the hull design and preferred engine specifications, the components are individually designed to achieve maximum performance and efficiency.

The company also makes ride control components, including roll fins, interceptors, trim tabs, and T-foils.

Advantages in buying the whole technically advanced package include no unpleasant surprises or assembly problems. All the parts are assembled and checked prior to shipment.

As well as supplying to an increasing number of leading recreational boat manufacturers in the US, Europe and Australia, VEEM has been involved in developing propulsion systems for major passenger and vehicle ferry operators, super yachts, commercial fishing boats and military vessels. These include the Fremantle and Armidale class patrol boats for the Royal Australian Navy, patrol boats for Yemen (built by Austal Ships at Henderson south of Fremantle), and valve components for Australia’s Oberon and Collins class submarines.

COST FACTOR

It costs more to produce VEEM propellers due to the use of highly accurate CNC machinery and robotics, but, according to Brad Miocevich, the cost saving to the manufacturer is the fact there is no need for repeated sea trials to produce maximum boat performance.

“We have just had a large US manufacturer launch a new boat and it was doing 39 knots with its current propellers. They changed to VEEM and the boat achieved a solid 41-and-a-half knots and they are now marketing that boat as a genuine 40-knot vessel, which they couldn’t do before. So that result gives them the ability to sell more boats, especially in the US sports fishing market, where people travel 100 miles off shore to their grounds and want to get there and back in a hurry,” he said.

VEEM’s Director of Marine Propulsion also points out the use of advanced propellers that survive at high speeds reduces the warranty costs for the builder, plus reducing fuel expenses for the operator.

The use of high-tech computer-controlled machining equipment, robotic polishing machines and laser-controlled fork lifts to transport its products through the production stages has taken propeller manufacture into a new age. Human input on the production floor at VEEM is kept to a minimum and this means every propeller of a particular size and design to suit a certain vessel is exactly the same.

If a replacement is needed, an identical propeller can be reproduced.

The company has come a long way since it first introduced its new generation propellers at a boat show in the United States in December, 2000.

While it believes its product is faster than anything its competitors can produce, VEEM has a continuous research and development program in place.

A new product will be unveiled at the International Boatbuilders Exhibition in Miami in October and while it’s hush-hush for the time being, Brad Miocevich describes it as an exciting breakthrough, which will ensure the company stays ahead in its field. Meantime, the world continues to beat a path to the door of this pioneering Australian company.


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