It seems to boil down to battery
banks priced Down to $100 per Kw Hour. Pricing has dropped to roughly lowest $300 though 2-3 years further will be $100 !
So,a bank that'll give a run for,again,roughly 8 hours to get the vessel through overnight powering then into daylight to recharge bank and motor
simultaneously,EP will then break out.
Bank form factor and additionally higher PV efficiencies are contributors to more rapid penetration.
It's all about efficiencies and costs.A cup of diesel
has become quite efficient!
All the Best