WOW this is GREAT news! I am really happy about this!
I'm not sure why, but when ever anyone brings up electric boats, hybrids etc there is a fervent resistance from some folks. The boating world is full of different choices, such as the Dashew camp or the Pardey camp, but both camps are respected. Some folks decry with a religious certainty that anything electric has no place propelling a boat. I can't seem to figure why....
I don't expect this system to save me any diesel (though it might: see #4) I'm also not that interested in running many 120V appliances. To my eye the benefits of this system are still numerous:
Even with the inefficiencies, if you charge while running and then alternate (no pun intended) to the electric drive you'll only be motoring a little more than half the time. That's worth the inefficiencies of power loss and charging to me.
Look at where the motor is connected. It's after the transmission but parallel to it. ie you don't need the electric to be working to use the motor as a traditional direct drive motor. This makes it much better than a series hybrid in that you have an independent electrical system AND an independent direct mechanical system. If one fails, you have the other. Very few parts from the primary engine are needed to run the electric drive. Also, no parts of the electric drive are needed to run the regular engine.
Starting motor failure, starting battery failure, bad diesel, clogged fuel filter, clogged sea strainer, blown impeller, busted belt, low oil pressure, are but a few of the common things that could stop your primary diesel but would not stop this system from still allowing to have 13.4HP of electric as an instant backup.
This is closely related to #2. I get nervous sometimes motoring in close quarters, especially if there is current/wind. If my engine suddenly dies I can't expect to have the sails up, drawing, and the boat moving away from danger in close quarters. If you have an electric backup there are no worries when your oil pressure alarm goes off and you're motoring next to your marina's breakwater with an unfavorable wind. The electric is instantly available at full power with no warm up time
would get you out of trouble, buy you sea room or at least get you pointed in the right direction to help you sail away from danger. This might be enough to keep you off the rocks or avoid a collision with another boat if you engine fails at an inopportune time.
This link: http://www.thehurdles.com/epod_in_use.htm
Is to a guy who installed 2 electric "E-pods" motors on his Gemini cat. He left his outboard in place also. He documents the experience well. One of the great joys of the electric motors for him was motor/sailing. He might be sailing along at only 2knots, but with very few amps of power he could increase his speed to 4 knots and maintain the silent serenity and joy of sailing. This meant that he sailed a lot more
. Personally, I never motor-sail. I either sail or if I fire up the damn thing, I motor at full tilt because I tried to sail so long it's now getting dark. Instead of sailing at 2 knots and following that with motoring I would MUCH rather sail along at 4knots all day with the electric helping me along and never get frustrated at going to slow, and never need to fire up the motor.
5. Maneuvering under sail.
I Have sailed into anchor twice, both times were when my engine died on me. If I had immediately available power to get me out of trouble, I might be more likely to sail into/out of anchor and my slip much more often. Currently I could fire up the motor, warm it up, and have it on standby, but at that point you've ruined the joys of ghosting into your slip or anchorage and I'd just be doing it for practice. If I had immediately available power I think I'd sail into my anchorage all the time. You could then use the electric to set the anchor, which isn't always easy to do with much force under sail alone.
6. High torque.
The above link comments on how much torque these motors have. He is able to stop his Gemini cat in 1/2 a boat length with a strong following wind using the electrics. With his old diesel he said it would have had it at full throttle back and not been confident he could stop the boat. The electric would provide confidence for manuvering in close quarters. I imagine it might help my awful prop-walk issues as well because it would be turning slower.
While you sail, your spinning prop charges the 48V propulsion bank. I know that there are some absolute efficiency losses between the drag needed to charge and what you can get back in thrust, but sometimes (like when the rail is in the water) you have an excess of sail-power. It would be nice to bank some of this for future motoring. I imagine that sailing regeneration, alternating with using the electric could save a lot of diesel and strip a lot of time off an ocean passage. Especially one that goes near the doldrums.
To me this engine represents NO real downside from a traditional direct drive power-plant and a large number of benefits. I don't foresee a large number of hours motoring silently but instead I foresee see a huge increase in hours sailed vs hours motored. If I could use this to "assist" my speed while sailing in light airs, I would sail much
more. If I always had the full power (13.4HP high torque) of the electric attached to the main prop available at a second's notice I would sail into/out of my slip and into/out of anchor much more often. All this and the piece of mind of redundant main propulsion as well.
Bottom line. I like it. If my Perkins bites it, I'm putting one in!