Passagemaker Magazine

BEYOND EFFICIENCY

So far, my focus has been on propulsion efficiency. It is clearly important to understand these efficiency issues, but in reality I do not believe this will be the driving force behind hybrid adoption by recreational boaters. The core benefits of hybrid propulsion are quiet operation and freedom from exhaust emissions. Every time we took our test boat off the dock with no noise and no exhaust, all those around stopped and stared.

With hybrid power there is no more dockside idling, or idling in locks on a canal system. There is no more engine run time while in a harbor, because low-speed maneuvering is performed under electric power. Our powerful generator enabled us to consolidate six hours of engine run time for maneuvering in harbor into one hour of generator run time (or an overnight charge from shorepower, when available, with no generator run time at all).

A hybrid battery pack will be relatively large. For the hybrid to function, the battery pack will need a high charge acceptance rate. As a result, a considerable amount of energy can be put into the batteries in a short space of time, and the battery pack will support substantial house loads between recharges. On our test boat, in an extreme case we could put four days of house power into the batteries in 15 minutes of generator run time. On many boats it will be possible to power overnight air conditioning without running a generator.

Unlike propulsion power, at all times the generation of house power is far more efficient than in a conventional system, a topic for some future issue.

The powerful generator and large battery pack of hybrid systems are enablers for more extravagant lifestyles. It is these lifestyle issues—lots of house power and substantially reduced engine run times, along with the concomitant silence and freedom from exhaust emissions—that will ensure the success of hybrid systems. The greater the house loads and the more extravagant the onboard lifestyle, the more attractive a hybrid becomes. Any efficiency gains will simply be a bonus.

Whether or not a serial or parallel system is more appropriate in any given application will remain a complex calculation based on projected propulsion duty cycles and the current state of technology.

Too Complex for marine indus Try, d’an Tonio says
To his credit Calder’s two-part series on the subject begins
with, “for the past five years i have been involved in research
to determine if hybrid propulsion technology represents a
viable alternative to conventional marine propulsion systems.
i have come to the conclusion that the answer is a more or
less unqualified ‘yes’, [are these not contradictory?] but not
necessarily for the efficiency reasons cited by most proponents.”
in short, while making it clear that hybrid propulsion
isn’t as efficient as some have claimed, he advocates the
use of this technology to improve the quality of life while
afloat. Quoting Calder again: “The powerful generator
and large battery pack [associated with hybrid propulsion
systems] are an enabler for more extravagant lifestyles. it is
these lifestyle issues—lots of house power and substantially
reduced engine run times with the concomitant silence
and freedom from exhaust emissions—that will ensure the
success of hybrid systems.”
i’ve worked on and with marine propulsion and electrical
systems for more than 25 years, and one fact has been
made plainly evident to me, the marine industry is very good
at innovating, there’s no end to its creative and marketing
genius, it’s inspiring to be sure; however, we struggle when
it comes to supporting, maintaining and repairing systems,
particularly cutting edge technology.

even if one assumes hybrid propulsion systems are more efficient for onboard energy production or propulsion (something we’ve been told over and over again by a host of manufacturers, yet now after five years of intensive, well-funded study, Calder tells us this isn’t necessarily so), i remain reluctant to embrace them for one overriding reason: Hybrid systems are extremely complex, and i don’t believe their manufacturers or the industry at large will be able to maintain, troubleshoot or repair them efficiently and

The Great

THe Core Benefi Ts of HyBrid po Wer are Quie T opera Tion and freedom from exHaus T emissions. eVery Time We TooK our Tes T Boa T off THe doCK Wi TH no noise and no exHaus T, all THose around s Topped and sTared.