Multifaceted multihulls

Power catamarans generally come in either planing or displacement versions. The former may have larger engines and handle like a monohull powerboat. Trawler versions use displacement to add stability and economy, so are ideal adventure vessels or indeed party vessels thanks to their vast, stable decks.

Cruising on a power catamaran is popular in shoaling, sheltered waters where the main characteristics of the design come to the fore, and some of the tougher versions can even be beached. Places like the Gold Coast and behind the islands of northern Queensland are ideal powercat territory. Here, the high costs of berthing one in a marina can be avoided and the long-range fuel capabilities enjoyed.

Sailing multihulls reduces your carbon footprint significantly, especially if you choose a highly efficient model, but like much else in life, compromises have to be made.

These range from slower cruising styles that emphasise comfort over performance to the higher end of the spectrum with lighter-weight hulls and appendages for going upwind at speed. The latter also make for thrilling helming and can cover vast daily sea mileages. Greener auxiliary power can easily be used on these sailing cats, which again all goes to lessen your carbon footprint.

Fuelling the change

Technological developments in materials, software and engineering are creating incredible possibilities in the marine world, with many of them coming from fast-moving sectors such as automotive. For power boats, the key resource is fuel. Replacements for the finite fossil fuel is the holy grail that engine manufacturers seek.

Yanmar’s sustainable projects include using low-carbon fuels such as HVO – hydrotreated vegetable oil, a second-generation renewable diesel. It’s a similar story with Cummins and Volvo Penta; they’ve been involved in electrification for years, along with developing hybrid solutions such as an electric motor attached to a standard diesel drive train.

Hydrogen is also being tested by major companies. Yamaha unveiled a prototype hydrogen-powered outboard motor at the Miami International Boat Show 2024 in line with the European Green Deal Hydrogen Strategy to produce green hydrogen. This is seen as a key factor for the decarbonisation of the maritime sector, including for specific types of recreational craft.

For slower-moving displacement powercats, electric drivetrains are a reality, thanks to lithium fast-recharging batteries combined with technologies from drivetrain companies such as OceanVolt, Torqueedo – which has just been bought by Yamaha – and many others. Many of these systems for sailing vessels also offer hydrogeneration underway, as used in events like the Vendée Globe, where the propeller, spinning while the yacht sails, is used like a dynamo to generate electricity.

Sustainable interest

Earth’s resources are finite, and as such, sustainability is necessary in every aspect of life, including the boating industry. It’s estimated that half a boat’s ecological footprint comes from its manufacture, whereas a car, thanks to economies of scale, only produces 15 percent of this footprint in manufacture (but 85 percent during its actual use).

Incidentally, car use in Australia – and, by extension, marine diesel engine use – is particularly polluting because of low fuel standards, something the current government is trying to address.

This creates unnecessary pollution and increases the carbon footprint of vessels. The efficiency of multihulls gives them an immediate advantage in terms of fuel burn and emissions.

Recycling also remains challenging, and led to a major conference held by the European Boating Industry (EBI) in March 2024. The conference confirmed the availability of end-of-life (EOL) technology and the willingness of industry to work with governments to create a strong European regulatory framework. Countries such as Germany and Austria have already banned EOL fibreglass vessels from being put in landfill.

The circular economy is also a key part of sustainability. So a boat’s life from build to bust must be considered and costed. Aiding this is the use of materials that can be reused, which means building with less toxic resins, some of which can be separated from the fibres, while the fibres themselves are reused. Others are biodegradable, like flax, jute and resinated wood.

Design is another major area where efficiencies, especially, can be made. Last year, the International Maritime Organisation (IMO) brought in a design efficiency metric for existing ships – the Energy Efficiency Existing Ship Index (EEXI), expanding design efficiency requirements that had been previously limited to new builds through the Energy Efficiency Design Index (EEDI). Eventually, this approach may be taken to recreational craft as well.

Meantime, recreational yards keen on making greater efficiencies often adopt low-drag hulls with equally low windage topsides. Adding foils, as the hydrofoil ferries of old did, is now well established in the modern yacht racing world and increasingly being adopted by some cutting-edge motorboat builders.

Multihulls’ narrow, wave-piercing designs are a good base to increase these efficiencies, typically by the use of chines for increased volume above the waterline, and with flatter hull sections aft to promote speed.

Market snapshot

Our eclectic mix of power and sailing catamarans is intended to illustrate a wide variety of the latest designs from large and small builders. Large builders have the research and development capacity to push the boundaries, such as the first electro-hydrogen production (prototype) yacht, the Fountaine Pajot Semana 59 Smart Electric, which uses solar and a hybrid hydrogen-electric motor – effectively creating a near-zero-emission vessel.

Another incredible vessel launching soon, the MODX, uses retractable and inflatable sails to transform from a sailing catamaran to a powercat at the touch of a button.

It’s built from bio-sourced materials, including linen fibres and 40 percent PET foams, and uses twin electric motors for auxiliary propulsion. It should be making its debut in time for the Cannes Yachting Festival in September.

More conventional sailing catamarans, such as the new Bali 5.8, are intended purely as cruisers, yet the Bali has acres of saloon-top space for solar panels and the tall, slim hulls are fairly efficiently powered by twin diesel engines.

For those with deeper pockets seeking serious performance, Australian-owned McConaghy Boats produces efficient, light sailing catamarans, the latest being the MC75. The China-based yard is well-versed in high-tech carbon builds – it’s also building the America’s Cup AC40 yachts.

Similarly, there are the performance sailing cruisers from China-based HH, which use Morelli&Melvin-designed carbon hulls and are – I concluded after sailing an HH50 off the Gold Coast last year – incredibly well-built boats. The latest is their flagship HH88, which uses daggerboards for high speeds upwind and is intended as a rival to the larger Gunboats.

Both these brands allow cruising at minimum windspeeds, so make for highly efficient sailing catamarans that are capable of big daily mileages. Electric motors are also an option on some.

Powercats, and especially semi-displacement ones, have yet to benefit fully from renewable energy because the power-to-weight-to-performance ratio still requires internal combustion engines. But, as already mentioned, the growing market for them has attracted some new major players from a stable of traditional monohull powerboat builders, such as the Prestige M8. This 65-foot Italian-designed luxury cruiser can sleep up to 10 people and cruise at 17 knots, powered by twin Volvo Penta D8-600s.

A fairly close competitor is our Australian-designed and owned Iliad 77, the flagship in a popular line of long-range adventure-style powercats. Specifically designed for Australian conditions, that is remote cruising, thanks to long-range capabilities, they claim 4,000 nautical miles in displacement mode. Both these boats have flybridges, so three levels of living space. Also in the Iliad model range is the Iliad 53E, which is a hybrid-electric model, suggesting a more eco future for cats.

Yet another Australian designed and owned builder competing in this space is Longreach, which specialises in efficient hull designs to create long-range cruising powercats. The first models launched late last year, including the Longreach 1900. Its house systems include 6 kW of solar panels on the roof to supply a bank of six Mastervolt lithium batteries, and it has large inverters that can run all household systems, including the air conditioners, without the need for a diesel generator.

For those looking for exceptional performance, Voodoo Yachts in New Zealand has developed a range of hydrofoil catamarans with a unique Xpedition Wing system.

The system drastically reduces wetted surface area, thus allowing efficient high-speed performance, as seen on the FX85 model that claims a range of up to 1,200 miles using jet-powered engines.

“Our jets lower the boat’s draft to less than a metre, making it ideal for shoal waters,” says company owner Mitch Pachoud. Other energy-saving ideas the company is working on include natural ventilation systems and aircraft-style tinted/heat-resistant windows to reduce energy needs inside the vessel. “But there’s a lot more scope ahead to increase our hull efficiencies,” he adds.

Another powercat company offering foils is Aquila on its 36 Sport and 42 Yacht models. According to the company, the 36 Sport hydro-glide foil improves miles per gallon by 40 percent when compared to a competitor’s 36-foot powercat.

Looks like the cats really have got the cream.