The chicken-and-egg situation that’s held hybrids in a “we won’t offer them till the market demands it” circle could be broken by a new drop-in unit. Further, the project is taking a novel stance on funding so if you want to combine a holiday with promoting innovation, read on...

The first of these new hybrid installations is going to Venice for use on a standard 9m taxiboat, where it will, hopefully, demonstrate to both the taxiboat owners and the city authorities that it can reduce the endemic smog that lurks in the narrow waterways. This is at least partially caused by the low-load running of the existing water transport, said Dennis Doerffel of REAP Systems.

The issue has been that taxiboats need to cope with fast, 30kn-plus transits outside the Venice lagoon “but inside the city boundaries the drivers are constantly clunking the engine in and out of gear: even idling the boats can’t keep within the tight 3 or 4kn speed limits” he explained. It’s not just bad for noise and emissions, it’s also bad for the owners’ maintenance and fuel costs.

Therefore the city as a whole stands to gain substantially from higher engine efficiency.

However, in order to be of interest to the taxiboat owners, it has to be installable, affordable and above all, reliable – given the usual 20 hour a day duty cycle. Dr Doerffel is adamant it has to avoid the traps that swallowed earlier green-transport attempts: “There have been government funded one-off projects that haven’t been commercially viable and even some outright failures; to be honest Venice isn’t keen on pure electric boats as they now think they need a fleet of rescue vessels to pick them up when the batteries run flat.”

To answer these concerns REAP has acquired a 9m taxiboat and is designing the installation to fit the ‘standard’ architecture and engine layout – luckily the boats tend to be fairly similar: “We are designing the unit to sit together with a Hyundai marine engine,” he explained, a V6 tailored to 170hp local regulations.

The electric motor and engine are both connected in parallel to the MerCruiser Bravo III sterndrive - but the engine can be clutched out he explained. This allows pure electric running for slower speeds or diesel operation which can include recharging the batteries, plus a possible ‘boost’ mode for clean acceleration. And it’s quick – the planing hull will get the most from the boat’s 30 or 35kn top speed.

It’s a high redundancy system he explained: “The boat can still operate if either the diesel or the electric propulsion system is down,” something that should satisfy Venice’s sceptics. The control system is fully electronic and the motor can be controlled down to very low rpm: forward and reverse achieved without shifting gears. Plus, because the transfer between modes is automatic, “it will be like operating a normal diesel” although there’s a driver ‘override’ to allow for manual selection.

Although all this may sound straightforward, he explained: “The risk is high. If you do something fundamentally different, you always find issues... take the outdrive for example: suppliers usually know how to size for diesel, but not for electric motors, the whole torque character is different to liquid fuel.”

Further, where the batteries are placed will impact the hydrodynamic character of the boat, and given the tight space – the hull has a fine entry carried back to a 2.23m narrow beam – there are very tight constraints and the whole trailer weight will have to come in below 3.5t including fuel.

Therefore REAP has partnered up with a number of experts from Hyundai SeasAll, Scorpion RIBs, WSX Enterprise, Southampton University, and the well known Joost Mastwijk - marine propulsion consultant “and mechanical design genius” said Dr Doerffel.

“The crowdfunding idea is a complete reversal of how the industry normally works - holding back your intellectual property advantage as long as possible,” he explained. “But I believe that we need to get the ideas out there. We’ve been stuck in a circle for so long: the main manufacturers say ‘we won’t do it unless the others do’, and people can’t just go and buy a hybrid unit ‘off the shelf’ because there isn’t one on offer.”

So depending on the amount an individual puts into the crowdfunding, there will be a range of ‘thank you’ benefits, running from taxiboat rides to a free holiday at the Venice partner’s hotel.

And of course, some ‘demo’ outings on the boat itself.

By Stevie Knight