Hybrid Propulsion solutions

Twin Disc, market leader in the segment of inverters and transmission compounds, is enhancing its marketing activities for the latest diesel propulsion system, known as Blue Drive, ideal for workboats or leisure units developing 60 to 150 Hp

Online PR News – 09-July-2010 – – San Matteo Decima, Bologna, Italy, July 2010

Twin Disc, market leader in the segment of inverters and transmission compounds, is enhancing its marketing activities for the latest diesel propulsion system, known as Blue Drive, ideal for workboats or leisure units developing 60 to 150 Hp.

A sea-trial was put in place in the Mezzo lake (Mantua area) on 14th May, within an event sponsored by the Mantua Province and Regione Lombardia. Such trial could be considered particularly testing, as it was carried out in a thinly balanced ecological environment.

The same moto-topo (a typical Venetian heavy duty workboat) has been widely utilised by Twin Disc in the Venetian Lagoon ever since its introduction in 2009.

Agostino Amadi, owner of the Burano-based shipyard owing its name to its creator, captained the units during the sea-trials, which gained favourable reviews from the passengers invited to the test.
Claudio Bassi, project engineer for Twin Disc, also attended the event in order to supervise matters and assist various Representatives from the local and regional Companies and Public Entities.

Leaflets and other sorts of items were handed to the extent of illustrating the Twin Power product, an environment friendly hybrid propulsion system, whose main features were unveiled at the latest Genoa International Boat Show, amid a dedicated press conference, branded ³Boating runs to meet the environment².

PhD Engineer Claudio Bassi of Twin Disc, leading company for the construction of reversing gearboxes and transmission systems, was amongst the speakers at the event, and he presented the audience with a report titled "Ethics and Propulsions: how to face the issue, from a leading transmission manufacturer's perspective".
The constant research for innovation and "green solutions" are at the very core of the values purported by Twin Disc, a company which has been in business for more than 35 years through its brand Technodrive.

What Twin Disc proposes is not a mere exercise of environmentalist demagogy, rather it is a technical reality as two new diesel/electric transmission systems have been placed on the market.
The "Blue Drive" series is addressed to commercial boats and yachts spanning 60/150 Hp, while the "SeaProp60" series can be deployed on 9-20 m sailing boats.
Before going into any further detail concerning "Blue Drive", however, it is necessary to further analyse, and illustrate, what a diesel/electric engine group consists of.

The possibility of developing a "no-impact" electric navigation has come to the forefront of environmentalists' concerns following the introduction of particularly strict regulations for lacustrian and/or protected area navigation.
Towards the end of the 1980's, a variety of European entrepreneurs and ship builders began to utilise diesel/electric propulsion systems on a number of diverse applications, however such solution had initially appeared not to be too viable for a few reasons.

The application costs were deemed too high, additional mechanical parts had to be put in the frame, the overall weight of the system was usually out of proportion and loss of power was a frequent complaint with such kind of system. That notwithstanding, a growing integration with the electric elements down the years has rendered this option a well balanced and accessible one, to the extent of considerably reducing consumptions for small and medium size yachts, and for larges ships, including freighters, ferries and cargo vessels.

A dual propulsion system of this kind presents many a benefit and can easily be deployed where even stricter navigational restrictions apply, i.e. canal cities such as Venice, Amsterdam, Copenhagen or, for that matter, in lacustrian or otherwise protected areas.

The equipment can be deployed in at least four modalities: electric engine navigation, thermal engine navigation, apportioned navigation with propulsion balanced between the two systems and, finally, there is also an option to recharge the system's batteries, at least when the ship is in idle mode.

That only a handful of kW are capable of developing a 5-6 knots speed even when applied to larger ships, has surely been one of the contributing factors to the widespread, worldwide in fact nowadays, distribution of such sort of system, although it is to be considered that it is best applied to low-speed boats including sailing yachts, barges and dinghies.


Twin Disc, in its pursuit to show the extent to which yachting and ecology can be matched, has identified and outlined six key areas, items around which their commercial proposal can be developed:

1) What is the most common utilisation of a yacht? A boat is usually berthed in the port and can be deployed for daylight outings, generally for two-three hours, at low speed navigation.
Obviously, it must be equipped with sufficient batteries to cover the navigation time and then have the possibility to recharge such batteries while utilising the normal combustion engine.

2) What kind of vessel is best suited to the utilisation of a dual propulsion system? Sailing yachts, of course, workboats, passenger ships (taxi-boats, touring boats) operating in lacustrian areas and lagoons, rivers, canal cities.

3) Is this proposal a switching kit or a proper system? An integral system is such when it is compatible with whatever builder's engine group, a not-so-invasive kit system, compact, modular and simple.

4) What sort of power and for what sort of employment? Just a handful of kW, able to develop a 5-6 knot speed, but with electronic controls to guarantee easy and prompt manoeuvrability, accuracy, and dependability, not to mention that such system guarantees a virtually noise-free navigation courtesy of an electric engine versatility.

5) Parallel dual system or serial dual system?
Both systems should be sized to the operating power where they can provide the most benefit, that is : low to mid speed cruising.

A "serial dual system" is seemingly the easiest solution, as it would undoubtedly be easier to install on a new building.
The serial dual system breaks the mechanical connection between the engine and propeller shaft.

In a "parallel dual hybrid system" the motor & generator functions can be combined in one unit saving weight and cost.
A parallel hybrid thus give improved efficiency at high power compared to a serial hybrid.
As it's name implies, the electric motor acts on the drive shaft in parallel with the engine. You can drive the propeller directly from the engine or from the electric motor or from both. You can also disconnect the propeller for a stand-alone generator function. During re-generation the engine is disconnected.

Moreover, such option is less "invasive" and, on top of that, it would also be easier on a serving boat as well.
The Twin Disc solution is substantially a parallel hybrid: it is intrinsically more reliable than a serial system. If an electronic component breaks down then this would disable a Serial system. If a parallel hybrid breaks down then the engine can go on happily providing propulsion in the usual way.

6) What sort of technology? Twin Disc's Research and Development Division has been active and involved within the domestic scientific community (universities, small and medium enterprises, cultural foundations). A melting pot of intelligence, know-how and locally based sources, spanning from electric engine builders to electronic parts projects, all sourced on the domestic markets.

As mentioned above, this kind of transmission is suitable for 60/150 Hp commercial vessels and yachts and tests for its implementation have been carried out on a motor-prototype (8 tonnes a cargo, 18 tonnes full cargo) in the Venice lagoon since March 2009.
Its technical parameters, inter alia, consist of a 6 kW electric engine/generator, 96V cc energy supplying tension, and the system can work at a full regime for up to 2.5 hours, according to the kind of batteries it's equipped with.

The generator/engine machinery group, including the related transmission box, reaches a maximum weight of 37 kilograms.

The brand new Blue Drive system is marketed, in Europe and Australia, since April 2010, and its cost is roughly 25% better off, if compared to similar products from other companies.

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