Nice unit - no doubt.
https://power-pole.com/charge
Essentially a combination unit that is charger, emergency start - so it apparently contains a battery, and some line switching capability.
By all means, if you like it go for it.
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Or if you have multiple batteries in the boat and jumper cables, you can do essentially the same thing for the bulk of the applications.
But, if you like it - I expect that it will do a nice job for you and your boat and power needs.