Wow!
that's really got me thinking! Thanks everyone for your input.
I'm contemplating a narrowboat but I haven't fully investigated my options and financial implication yet.
I guess what I need to take into consideration is that the same problems will arise as in a shared house only amplified because of the confined space.
Bones, you make a good point, it is ultimately down to me whether It's lonely or not. My plan is to live on a stretch of canal very close to friends so if I choose to live alone I can have an open door policy!
I think all things taken into account, if I choose to have a friend onboard it will have to be a solid friendship and a big boat.
I also hadn't taken into consideration the flexibility and changeability of living afloat; if I did want to move on or if my circumstances changed I'd a bit tied down by the implications involved for the other person.
When I picture it in my head I picture just myself on my boat and I think that says it all really, so on that note (and to flip this topic on it's head), can anyone give me some hints and tips on living alone afloat?