Welcome! Glad you came in out of the cold! But I might point out that most of us do not have an engine block, FWIW. Other than that little detail, I agree with you, of course.
I will point out to the new guys though, that when you do properly ground your bank and your electric drive, the "One Hand Rule" also includes touching any grounded metal with your free hand while working with the other. Accidentally touch 48v+ with hand or tool, while the other hand is supporting or steadying you by holding onto something at 48v-, and you are in for an unpleasant experience. Probably a scary one. Or worse. Yes, 48VDC is considered nonlethal. That doesn't mean it can't still kill you when your arm, chest, and other arm complete a circuit with a battery capable of discharging briefly into the hundreds of amps. Essentially, the current through your body would only be limited by your body's not so terribly high resistance. So just remember, ground isn't just ground... it is -48v, relative to the hot end of your battery bank. And commensurately less at other points in the bank.
I was just looking at some electric car forums and thinking about that, because commonly, DIY e-car builders leave the battery pack ground floating, rather than bond it to chassis. They commonly use 120V or higher, sometimes much higher voltage, which is potentially lethal in anybody's book, and who hasn't leaned against a fender and gripped some unpainted steel for leverage while working on a car? A slip of wrench or screwdriver while diddling around with 280VDC or so, while holding on with the off hand to bare steel that is tied to B-, could easily kill. I think that is actually one reason why they often do NOT ground their battery packs to chassis.
Don't get me wrong... I am NOT saying don't ground the battery bank! (and there is a big difference between typical car and boat voltages.) I wouldn't think of not grounding my own bank. I am just saying that if you do, which I think you should, you need to respect all grounded metal for what it is, when working with +VDC. This would be especially true on a steel or aluminum boat.
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