While I can see how one's footprint would be far smaller than living on land, It is all relative, and I'm starting to think that contrary to myth, often it is far from a really minimalist lifestyle.
A minimalist lifestyle goes with the person not the place. You can live in a cabin or an apartment and be a minimalist in both places. I am a live-aboard for over thirty years and still donít have TV, GPS or anything else thatís considered standard equipment today. But I do have maintenance on the boat and her equipment and it looks like my cost is much less then yours because I do it all myself. I think self reliance and a minimalist life style go together.
All the best,