Seattle shipbuilder to unveil the world's first hybrid tug

Seattle shipbuilder to unveil the world's first hybrid tug

Foss Joins U.S. EPA SmartWay Transport® Partnership TO IMPROVE ENERGY EFFICIENCY AND AIR QUALITY
http://www.foss.com/press/SmartWayRelease.html

Seattle shipbuilder to unveil the world's first hybrid tug
http://blogs.business2.com/waterlog/

 

I remember reading about this a few months ago. Thanks for posting it, George!

Harbor tug service should be a good application for the battery cycle of hybrid power, just as urban driving is for cars. Standby and on call times would benefit from battery operation, with the diesels shut down, rather than idling for hours. One question I have, though, is how they will handle diesel on-off cycling. Hybrid autos turn the gasoline engine on and off in sometimes brief cycles in urban traffic. I don't see multiple start-stop cycles being good for the life of a diesel engine, and a significant portion of the pollutants come during the time after cold start, before the engine is up to normal operating temperature. I'm not saying it's not a good idea, just wondering how those details are handled. I've read several articles on this, as well as Siemens ELAS hybrid marine propulsion system, but they all simply make generalized claims of "more efficient" operation of the combustion engines.

 

As I understand it about 60% of new tugs and commercial ships including large cruise ships are Diesel to Power Converter to Electric Motor powered.

What makes this Tug different is the use of batteries I think, but I could be wrong.

This means the batteries are the part of the power converter system, and it's the batteries powering the motors. The Diesels come on only to charge the batteries I think.

It's the long "stand-by" peroid which makes this system different than a cruise ship with a seperate power system which provides "house power" and another system for propulsion.

What I get a rise out of is that the port authority gave them money. Such is politics.

EDIT
I should note that for some military and cruise ships "gas turbines" and steam are used to generate electricity. This might be part of that "60%" number, I'm not sure.

 

If the tug is a Z-drive diesel->electric->motor makes sense. Modern cruise ships use electric Z-drive pods. So that would be quite easy.

If the tug is of the "squirrel cage" propulsion design, and is electric, then I would really be impressed. I dont think anyone has that before.

The press releases don't give those details.

 

Foss has been adding single Schottel Z-drives on the back of their Voith-Schneider-propelled boats. They call it TractorPlus. These are directly connected to an additional diesel engine.
BTW, there's an amazing size difference between a new 1700hp engine and an old 1500hp engine.

I really can't see them going with an electric eggbeater. Foss is not in the business of developing propulsion machinery, and nobody else (that I know of) has it on the market.