It sounds like the lifestyle would suit you, I'd suggest you go for it.
You've highlighted your potential biggest problem yourself: water. If you insist on having a 10 to 15 minute shower every day you're going to need to fill up every few days. Imagine: it's winter, pouring with rain, dark and freezing cold outside. You've just got back from work, the boat is freezing cold. Do you get a fire going to warm up, make yourself something to eat or face the hour or more journey to get water in the dark?
It's already been suggested but you can wet yourself in a few seconds then turn the water off. Then soap etc. Turn the water back on and shower off, maximum a minute or two. Or, just have a wash sometimes rather than a shower, it works!
If you can't face not having a long, hot relaxing shower every day I'm afraid it's likely to scupper your wider lifestyle plans.