Inside Motor Yacht Kismet’s Engine Room

Triton had the exclusive opportunity to speak with a chief engineer, who preferred to remain anonymous, on board M/Y Kismet about Kismet‘s engine room. From its hybrid propulsion system that includes PTI (power take-in electric motor) and PTO (power take-off generator) to its “Tron corridor,” the chief engineer told Triton all about the 122-meter, Lürssen-built vessel’s cutting-edge engine room. 

From an engineering perspective, what’s unique about Kismet? 

Definitely the Multi-Drive, 100%. The Multi-Drive is the collective term that we use to refer to basically everything from the shaft generator/propulsion motor, or PTO/PTI as it’s known, to the battery bank, to the way that it actually comes in and complements the main switchboard. The whole unit can be self-sufficient away from the main switchboard, but equally can connect to the switchboard, so that the power can flow in each direction — we call that the energy flow. 

What’s the benefit of the hybrid drive?

It’s virtually silent. We’ve got a yoga studio and a massage room back aft, underneath the shaft line. If we’re driving the boat electrically, there’s almost no noise back there, it’s almost completely silent. We also use the batteries to peak shave with the generators, so if the generator is running and a big load comes on, the batteries will support the generator to take that load. Then when the load drops off and the generator has a bit of capacity left, it uses that capacity to return to batteries. The analysis I use is that it’s like a Lexus hybrid as opposed to a Tesla. It’s not full electric, it’s hybrid. Our consumption is actually very low. When we’re cruising, because we’re not running a generator, we’re burning about 700 liters per hour total at cruising speed, about 12 and a half knots, so that’s very efficient for a boat this size.

How many generators do you have on board and how do they work?

We have three generators with the battery bank. We never called for a second generator because the batteries always come in and support the generator when the load is a little high for a short amount of time. We run on one generator almost all of the time — we have had one generator on since the last guest trip that we dropped off, which is remarkable. The other thing as well is that, when you’re underway, if the weather is not so good and the boat is rolling, the stabilizer fins are large transient loads that come and go. They’re just there for a moment and then they’re gone. Whereas in the past, a second generator would have been called online to take that load and it would never have had the time to drop off, because the load comes back. On here, the batteries come on, take the big load, and then the load is gone. For those few moments before the fin goes in the opposite direction, the generator is feeding back into the batteries, so the energy that you’ve taken from the batteries goes back into the batteries and charges them right back up. 

How does the Tron system work?

It’s interactive, it’s touch screen, so you can pick any piece of equipment in the engine room and just touch it. When we’re underway the data is live, it’s taken from the alarm and monitoring system so [it shows] the actual RPM of the engine, how many kilowatts we have, the speed, so it’s one of the best things I’ve ever seen.

Is there anything Kismet doesn’t have that you’d want? 

There’s not much! The only thing that they could dial in a bit better, which we could still do in the future, and we probably will — we have waste heat recovery on the generators. When the generators are running, we’re using the jacket water from the generators to heat the water. Our domestic water, our deck, and the pool water was heated by the generators — we’re not using any electricity for that. The only thing that we found now is that when we’re underway we’re not running the generators, so then we’ve got the shaft generators on, and we don’t have waste heat on the main engines.