Aaron,
It's all about money and weight. Electric hybrid allows infinite distance, instant startup for emergencies, the efficiency of an electric drive (and yes there is efficency in electric drive over ICE direct drive).
My boating preference is to start early in the morning, before my other half is up (Starting a I.C. engine wakes her up). Within an hour she is stirring and the engine can be started without waking her before needed. Depending on the battery type, the battery bank can be fully charged and I can find relief from the noise again, for another an hour or so.
The battery bank can be somewhat small for short bursts. I can have the ability to use any power appliance I want aboard. Electric drive is efficient no matter what speed I travel. Motor size limits top end of the boat but the full range of speeds are governed by drive efficiencies not engine size efficiencies as is the case with any I.C.E. system you install.
You must consider prop slip requirements and diameter requirements when installing a complete I.C. system, and size the engine for low speed startups and getting out of the hole for planing hulls. On the other hand with an electric system the torque is the same for the full range of RPM. What this means is low slip high efficiency prop selections can be utilized making a more efficient system over all.
Any Genset is designed for the engines most efficent range, so losses are limited to heat engine design constraints(there is no such thing as perfect). The turn to I.C. drives in boats in the past development, displayed to all the advantage and disadvantages of both drive systems. When overall economy is required, as in cruise ships, a Hybrid system is used.
Electric boats need not have a limitation, or an all or nothing choice. Fitting a genset on a house boat is likely a good choice for the comfort that most passengers expect. Electric drive avoids the requirement and inefficiency experienced by fitting the house boat with I.C.E solutions for drive as well as electricity. This type of model is well developed and tested in the cruise ship industry so why fight it.
As an additional reference, the Tempe Town Lake has/had a tour pontoon boat driven by electric motors. The drive was designed by SRP ( the local power company). The charge station is located at the dock and the boat is recharged in-between tours of the lake.
The tech is here today, and has been for many years. We are not on the forefront of new technology. We have new methods brought on by innovation, but we are, only now more conserned about our environment and willing to make compromises in what we expect, to save it.
Kevin Pemberton
On 11/02/2010 03:21 PM, Aaron Costic wrote:
You are right, I was thinking of an all electric drive rather than a
hybrid. With a gen set as a back up to charge the batteries. It would
probably take a pretty hefty battery bank & 2 large electric motors to
safely power the houseboat. Top speed isn't important. A range of 3-4
hours at 8-10 knots would be adequate. Do you think the technology is there
now?
Aaron Costic
Elegant Ice Creations
www.ElegantIce.com
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