Is it true that any sailing yacht is greener than the greenest and most efficient motor yacht? I strongly believe so.

After being aboard the new 96-footer Nyumba, the first Southern Wind sailing yacht with a diesel electric Hybrid propulsion system, my beliefs are even stronger.

Having a very efficient power management on board offers the opportunity to the Owners and their guests of a completely silent cruising experience, no matter if they are weekend cruisers or round the world sailors. Thanks to the battery capacity and the high recharging speed offered by the generators, Owners can spend most of their time on board without hearing any machinery noise. The benefits are even higher when the wind is blowing.

HybriGen® technology, thanks to the ability of the system to regenerate power via the controllable pitch propeller, produces enough zero emission energy while sailing at 10kts to sustain the yacht electric balance. When sailing at higher speed the Hybrigen system generates up to 30kWh (@15kts), recharging the batteries and allowing silent anchorages with no generators running.

The system also offers the unique opportunity to extend the yacht range and autonomy, saving fuel otherwise burnt during offshore sailing passages. This would be a game changer for those Owners with ambitious exploration programs because they could reach remote destinations while sailing with zero emission and start their cruising with full fuel tanks.

What excites me even more is the fact that the innovative Hybrid System, conceived in collaboration with BAE System, has been engineered to fit in the engine room of a yacht of only 96 feet (29.3m). The footprint and the weight of this sophisticated system is impressive for the performance it can achieve, especially if compared to any other similar system.

IMO compliance, comfort and longevity

An important factor to consider is the new, stringent IMO Tier 3 regulations affecting all new marine diesel engines with a power output greater than 130kW (174hp). This regulation restricts the navigation areas for noncompliant vessels in certain geographical areas. 

With a hybrid system such as the one fitted on SW96 Nyumba, powered by two relatively small generators instead of one big propulsion diesel engine, yachts over 24m (82 feet) can circumvent such a regulation. The nitrogen oxide (NOx) reduction requirements of IMO Tier 3 are a challenge for yacht builders because the solutions that have been developed for commercial shipping such as selective catalytic reduction (SCR) are impractical for a sailing yachts with a 300-450hp auxiliary engine.

Another significant benefit of hybrid drives is their longevity. In conventional installations, a yacht’s gensets are typically replaced or completely rebuilt within 20,000 hours and the engine after about 25,000 hours. By contrast the BAE Systems HybriGen drive is rated for 52,000 hours of running.

The next generation of hybrid powered sailing yachts is here.