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.