A 42 foot luxury catamaran called the Lagoon 420, which uses an innovative diesel-electric hybrid engine, was recently launched:
The latest version of the electric motors made an impression as she left the docks in silence. The electric motors had incredible torque, smooth acceleration was provided while working the throttles. The soundproofing of the genset compartment worked extremely well.
The “Hybrid Diesel-Electric Propulsion Drives” seem pretty straightfoward and sensible:
Complete installation comprises of two standard electric motors connected to propellers by straight shaft transmissions, one generator and two set of 6 batteries.
• When batteries are 100 % charged, the boat will be able to function with both motors for approximately two hours (depending on speed).
• When batteries are 80 % charged, the generator will automatically start and charge the batteries in order to provide electricity for the motors.
• When sailing, propellers will turn freely and recharge the batteries.
They even have survey results for the question “What do you consider important about a hybrid diesel-electric multihull?” Not the most scientific-looking survey (e.g. they just added a fourth choice and are mixing results), but still interesting.
The main question NEVER seems to be addressed and I wonder why…
With losses, a single 11/13KW generator will only be able to power 2 x 8/10KW electric motors at about 1/2 power. So, when the batteries are 80% depleted and it starts what is the best sustainable cruising speed obtainable, what is the consumption and the range?…
My personal guess is 5 knots max, which is just not enough….