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Old 04-02-2014, 08:43 AM   #37
Nick14
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City: New England
Vessel Name: Culmination
Vessel Model: Helmsman 38 Sedan
Join Date: May 2013
Posts: 719
In the last two issues Passagemaker magazine has had a couple of interesting articles on marine 'hybrids'. What I took away from the articles was, under specific and narrow conditions, and at very slow speeds (under 5 kts), under certain conditions a diesel-electric serial hybrid system might be somewhat more fuel efficient than a conventional diesel engine, because of the ability to run a smaller diesel engine at its most efficient speed (though they made a lot of assumptions in the articles, including 90% conversion efficiency). Otherwise, most of the scenarios they modeled seemed to show a conventional diesel engine being more efficient. There were also some comments in the articles about the complexity and associated reliability issues with a hybrid system (and removal of a system in a boat).

twistedtree and Ski, I think you hit the very heart of the issue - a car can benefit from the energy recapture of regenerative braking, a boat cannot. With the inherent losses of converting from one form of energy to another, I find it hard to imagine how a hybrid system could be more efficient under most conditions in a boat.

To me, the photovoltaic solar cell array is an interesting idea. Of course, being able to power around for 'free' is very appealing. But, while the theory is attractive, the practice is a little different. With the low efficiency of solar cells, the relatively limited space available for the array, and the need for strong sunshine, I think Greenline claims that in strong sun the array could move the boat at 4 kts. Not bad, and OK for puttering around a harbor, but not enough to deal with any kind of current. If it would be possible to get solar only propulsion up to 7-8 kts, then I think it could be a much more attractive and viable proposition (in Florida at least, not in the cloudy PNW), but that would probably take a major advance in solar cell conversion efficiency (and battery capacity to have more useful range).

I looked at the Greenline 33 and 40. Every boat is inherently a compromise and can't appeal to everyone in every way. For my own personal tastes, there were things I liked very much about the designs, and other things not so much. I personally like the 'super displacement' hull design, being able to cruise fuel efficiently (under diesel power) in the low to mid teens is right where I want to be. I also liked the general layout of the boats, with the walk-around side decks and retro profile.

I didn't like what I thought was poor engine room access in the 33 (you have to lift some of the salon furniture and move other floor and other panels, and then have to be a bit of a contortionist, or at least more limber and thinner than I am). I also personally am not a fan of the glass rear bulkhead. I appreciate that it makes for a great dockside party platform, opening up the salon and lowering the transom and all that. I personally prefer a solid bulkhead with a more weather and sea-proof door. Some of the hardware on the boat (cleats, etc.) also seemed a little skimpy, but small stuff like that can be easily upgraded.

For me, it's an interesting concept, and one to watch. Like any first-generation technology (early cars, the first PC's, etc.) it's far from perfect and I won't be one of the early adopters, but hopefully future generations will continue to evolve and improve.
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