E-Ship 1 exists: https://en.wikipedia.org/wiki/E-Ship_1 https://en.wikipedia.org/wiki/E-Ship_1 They report fuel savings up to 25%, so it may be viable for some

E-Ship 1 exists: https://en.wikipedia.org/wiki/E-Ship_1 https://en.wikipedia.org/wiki/E-Ship_1 They report fuel savings up to 25%, so it may be viable for some ships types and voyages. But a long way from propelling the whole ship.