Aventura Zero: Concept & Special Features

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Read the latest on Aventura Zero on Jimmy Cornell’s Aventura Zero blogs


Jimmy Cornell explains the concept which led him to commissioning the new Aventura Zero. Read more about the background to the voyage here.

Having launched the Elcano Challenge, and with time being of the essence in finding a suitable boat, I was fortunate in persuading the Outremer boatyard to take on the challenge of modifying one of the their existing models to meet my
specifications. The main reason for choosing a catamaran was the fact that I wanted to be able to complete under sail the entire route I had in mind. Therefore the boat needed to be entirely self-sufficient and for that it had to satisfy four essential criteria.

  • A potentially fast boat under sail.
  • A boat that has sufficient surface available to display solar panels.
  • A crew with the right attitude and mindset: capable and prepared to sail whenever there is wind and be patient to wait when there isn’t.
  • Following from that – and this is perhaps the most important factor – to accept that we now live in a world and a time when we must be ready to change our ways, from what we eat, how we live, how we travel; and certainly how we sail.

The first two of those factors were dictated by the need to generate electricity not just by passive means (solar and wind) but primarily by an active source: hydro-generation resulting from the movement of the boat under sail. Hence the choice of an Outremer performance cruising catamaran.


The Finnish company Oceanvolt have been working for the last twenty years on perfecting electric propulsion on pleasure craft. Two of their electric sail drives will provide propulsion for Aventura Zero. Oceanvolt have produced an ingenious system based on their patented ServoProp variable pitch propeller.

The unique feature of the ServoProp is the possibility to turn the propeller blades by more than 180 degrees. The software controlled variable pitch saildrive adjusts the pitch of the propeller blades automatically so that both the power generation and the power output are always at an optimal level.

Energy generation

The configuration of the specially designed blades is capable of delivering optimal efficiency both forward and reverse, and also in hydro-generation mode. With the blades set to the neutral sailing position, the propeller creates very low drag similar to that of a feathering propeller. The ServoProp is capable of generating an estimated 800 to 1000 W at 6 to 8 knots.

In addition, Aventura Zero will also have a large amount of solar panels (1300 W).

With such a high potential of generating electricity there is no need for an auxiliary diesel generator. Although the boatyard insisted that I have a backup diesel generator, I absolutely refused. I would not even agree on having a sealed unit to be used in a serious emergency, as I am determined to prove that cruising with zero carbon emissions is achievable, as is the possibility of producing a totally self-sufficient cruising boat. I shall even avoid using shore power at the stopovers en route.

Most of this is not new to me as I didn’t have a diesel generator on any of my previous boats and relied on the main engine for charging, in later years supplemented by solar panels, wind and hydro-generators. I had the opportunity of testing such a system on my return from the Northwest Passage when the engine failed shortly after leaving Greenland. We managed to sail over 2000 miles to the UK relying primarily on a Sail-Gen hydro-generator that covered all our requirements: autopilot, instruments, communications, electric winches and toilets, and arrived at Falmouth Marina with fully charged batteries.


As on my previous three boats Brookes & Gatehouse will supply all onboard electronics and have worked closely with Outremer to provide Aventura Zero with a state-of-the-art system worthy of the purpose of this project.

Aventura IV’s nav station

Aventura IV’s cockpit setup

The B&G Zeus3 system worked perfectly on Aventura IV and a similar system will operate on Aventura Zero.

Besides the standard offshore cruising configuration, B&G have agreed to my suggestion to use the new Aventura as a test bed for possible solutions in such common emergency situations as lightning strike, autopilot failure or power blackout. This was one of the main concerns expressed by cruising sailors who took part in a recent survey among short-handed crews. This was a perfect opportunity to test the feasibility of such an arrangement.


As I am setting off on a 32,000-miles voyage I want to be confident that we shall be able to deal with any emergency. An essential part of such self-sufficiency is having a separate emergency electrical circuit not connected to any of the boat’s networks, and thus protected from possible lightning strikes. It consists of an independent autopilot processor, with its own compass, Triton display unit, and wireless wind sensor.  An emergency 1200 Ah battery, charged by a Sail-Gen hydro-generator, would supply electricity not only to this emergency arrangement, but also to the service circuit.


The basic sailplan and rig are based on the Outremer 45, with some performance features borrowed from the Outremer 4X, such as a rotating mast, which should improve windward performance and also make reefing easier. Sailing such a challenging route that will be crossing several ocean regions, from temperate to tropical, high to low latitudes, I have put much thought into the sail wardrobe, by keeping it both simple and suitable for the expected conditions. Besides the standard mainsail and a self-tacking Solent jib, I’ll have a Code Zero sail and my favourite Parasailor spinnaker.

Hybrid version

As we ended up with several modifications to those two Outremer models, besides the electric propulsion system, this prototype will be marketed as a new model, the Outremer 4E. A later hybrid version, Outremer 4H, may incorporate a diesel generator with as low a carbon footprint as possible. But we are looking also at other, greener options.  However, as I expect that for some people the hybrid version may be the more attractive option, I have been doing some research into the feasibility of making diesel gensets greener than they are at the moment.  This led me to Krone, a major industrial filter manufacturer in Bremen, Germany, who have perfected an exhaust filtering system for one of the German Customs’ patrol vessels.

Discussing with Martin Krone and Björn Draack a greener option for diesel generators

Björn Draack, the Krone chief engineer assured me that a compact system based on a catalytic converter could be adapted to diesel generators used on pleasure craft. On my suggestion, they are already exploring this option with a manufacturer of diesel generators. However, by neutralising the noxious particles in diesel exhaust, a catalytic converter would only deal with some of the environmental pollution, with carbon dioxide still being released into water or the atmosphere. While this could be a start, I am sure that soon it may not be enough as it won’t be long before fossil fuel powered vessels will be barred from marine parks, nature reserves, some rivers and lakes. Therefore, if we really care about the future of the planet there is only one answer: we must go 100% green!

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