Originally Posted by Stumble
Again we get to an energy density problem. Lets assume that we design a keel so that the entire mass is one big battery. And let's assume that the design will keep the same density as raw lead (we know this isn't true, but it makes the math easier).
Some may a drifted this thread a bit but the original proposition was diesel / electric hybrid.
So we are talking about the energy density of diesel.
The trade offs are that it will cost more as you need more equipment.
It will not be as efficient as their are conversion losses but maybe not as much as might be at first supposed due to being able to run the diesel at optimal rpm and run the electric with optimal torque.
The only advantage, and for some of us it might be worth the extra money, is the quality of life advantage. IE for most passages you may not need to run the diesel at all but if you have to you can.
Also you possibly get the advantages of a genset without a separate diesel for that purpose.