Eh, everything that goes in the ocean requires a lot of engineering to survive. Batteries can be sealed if needed, electric motors can be sealed too. For example thrusters for ROVs are typically electric motors. They just enclose the motor in a housing and run the shaft out to the prop through a rubber seal. A lot of older stuff looks like it wasn't highly engineered because the important engineering was done a long time ago, and now the stuff is old and crusty. But there was a lot of work done to make gasoline engines work well in the water I suspect. We can do the same for electric.
> Batteries can be sealed if needed, electric motors can be sealed too.
A gasoline/diesel engine will just seize up when exposed to water, and if it's on fire it will be extinguished. Same for electric motors.
Batteries however? No bueno. Both the Americans [1] and Russians [2] lost submarines to battery fires. Batteries are hard and marine environments are among the nastiest you can get with corrosive saltwater and mist everywhere and continuous extreme mechanical shock events from waves and storms.
This is also why I believe that it's a fools errand to waste any non-fossil fuel (no matter if "sustainable" production from grains, frying oil or similar, or synth-fuels) on heating homes like it has been proposed in Germany or driving cars with it. The stuff is far too valuable, we'll need it for a long time to power aviation and maritime navigation until we get batteries both high-capacity and safe enough for these cases.
You overestimate the danger of batteries on boats. LFP batteries are commonplace on boats. Also, diesel electric propulsion is commonplace in large ships.
Nowadays, even small yachts are becoming hybrid or pure electric. My friend's 37ft sailing monohull is pure electric, so is my 35ft sailing catamaran.
My cat has a lot of real estate so I put a lot of solar. I rarely motor and mostly sail, but when I have extra power because the battery is full and the sun is shining, I can get a small speed boost for free. I have plenty of excess energy and have plugged into shore power maybe twice in the last year.
Many folks have a generator in case they need more range and there isn't enough wind. But I personally haven't needed it yet, but I also don't sail long distances. I would probably bring a generator if I did, in case there's no wind and I need to move.
My friend has a generator aboard but hasn't used it once yet, and he made it to Puerto Vallarta from SF.
I think pure electric is most common for sailboats. Where can get most of your propulsion from the wind and power from solar. My understanding is that range on electric is small. Fine for harbors but not enough if wind is wrong. It is usually possible to drift but that wastes time and can be problem in some situations. Most electric drive sailboats have a diesel generator as backup.
Power is common on a lot of docks. Just plug it in and charge it up.
Range is not really a problem if you plan carefully and are patient. I try not to motor much anyway -- it being a sailboat and all. I do have a back up generator though.
A gas tank, a propane tank, heck even a diesel tank, are all more dangerous than my LFP pack. Also my LFP pack weights 81kg, not a ton, definitely not multiple tons.
Larger boats are all diesel/electric series hybrids anyway (not sure if this is common at the scale of this particular vessel). Saltwater is nasty (and freshwater isn't great either), but avoiding electricity isn't easy.
One need not imagine such things. It took a week for the Freemantle Highway car carrier to stop burning, something 90% of HN denizens are blissfully unaware of due to narrative blindness, and only about 15% of its cargo was electric.
While a burning electric fishing vessel won't do well, understand that these operations are already fraught with risk and regularly experience minor disasters. The small operations are borderline piratic and the big operations are highly lucrative. It is unlikely that they will forgo whatever benefits they imagine due to some unquantified fire risk.
Teslas in NA use NMC chemistry (or a variant) which is much more dangerous than the LFP chemistry commonly used on boats. LFP cells are much harder to set on fire, and they don't burn anywhere as violently as more volatile chemistries.
