Hybrid Engine Systems and Sustainability

I agree that the previous poster is overly optimistic regarding his expected fuel savings and that his estimate of the power that will be available from his solar array is out of sight . I do think however that it might be possible to design a boat that uses a solar array instead of fuel for house needs as well as for powering an electric engine for slow speed maneuvering and short distance propulsion. Depending on the design sail or diesel could be used for long distances and higher speeds.

 

Please see magnum 53 hybrid post for more info on my post it is difficult to discuss on both but that was my fault so my apologies.

 

Yes, it certainly is possible to do as you say, but it needs a boat designed from the outset to have as low an energy requirement, both for propulsion and house loads, as possible.

One option is to look back at the times when engines were in their infancy, and produced limited amounts of power. Hull forms tended to be slender, with a low displacement and long waterline length, so they had a low propulsion power requirement. For good stability then using a stabilised monohull (essentially a trimaran with very small amas) maintains the low hull resistance at reasonable cruising speeds and also allows a larger deck area that can be utilised for solar panels.

Adding good insulation to the accommodation space reduces the energy consumption of AC or heating systems, as does using heat recovery ventilation or heat pumps using the high specific heat of the surrounding water.

If the main propulsion system is electric, with a large battery bank and and on board back up gen set, then such a vessel could be capable of long distance cruising reliably and economically. The key is holistic design of the whole boat, including all the systems, together with managing the expectations of owners so that they can learn to use their boat in the most efficient way. Lessons could be learned from modern house design, like the Passivhaus movement, which focusses on every source of energy waste and seeks to minimise it by design.

This doesn't mean that such a boat needs to be spartan or uncomfortable. With the right design approach it could have all the mod cons we expect, including heating, hot water and comfort cooling. I've yet to see anyone really grasp this as a concept; the majority of "eco" boats that seem to be making false claims as to their low energy credentials or just using the term as marketing BS. A pity, really, because I really do think there is a way to build practical long distance boats like this.

 

"One option is to look back at the times when engines were in their infancy, and produced limited amounts of power. Hull forms tended to be slender, with a low displacement and long waterline length, so they had a low propulsion power requirement. For good stability then using a stabilised monohull (essentially a trimaran with very small amas) maintains the low hull resistance at reasonable cruising speeds and also allows a larger deck area that can be utilised for solar panels."

This is more or less the way I came up with the idea for the concept for a boat that would meet my own requirements , similar to the op's, except that I require that high speed travel be accomplished under sail and that low speed travel and maneuvering be provided for by a small electric engine. I would wish to dispense with fossil fuels altogether and have all electric needs supplied by the solar array.

I came to the conclusion that the Hawaian sailing canoe was the ideal hybrid and chose it to model my efforts on. I have been pursuing this idea for a while now and feel I am getting closer to something that might work.

 

Interesting boat.

Those shades from the mast and sails will be a problem for solar panels: http://www.renewableenergyworld.com/rea/news/article/2009/02/shade-happens-54551
It can be resolved partially (!) by adoption of microinverters (one per each PV panel), but they cost $150 and add 2.5 kg each.

And I would definitely avoid putting solar panels on amas. In that position they are a risk for boat's safety in choppy seas.

Cheers

 

If flexible PV panels progress enough, they could probably be attached to the sails themselves.

 

Exactly! Jeremy, this is what I have been advocating all along. I propose a catamaran design [Wharram springs to mind due to self-build ease and sleek hull form...]. But a vessel incorporating all of your criteria and with the possible future development of my SKS [Solar Kinetic Sail] idea, a truly sustainable vessel can be realised. There are many other developments in the offing that would help to bring an efficient design forward, such as: sharkskin paint [...don't know of its real or trade name], utilizing the property of hydrodynamic boundary disruption [a phenomenon known for many years in the gas-flowing and porting of performance engines...]. The envelope needs to be pushed if these great ideas that we have can be realised. But your sobering technical input is vital to temper the passion and bring us down to earth [a bit]. I have learned much from your input. Thank you.