Living on a boat means you’re automatically more in touch with your neighbours, much more so than conventional London living.
I think it’s a combination of the shared way of life, the fact that you pass each other frequently on the pontoon, and perhaps the fact that moorings are generally locked, so people on the pontoon can only be other boaters.
We’ve recently changed moorings, and have found our new neighbours to be as friendly as our previous ones. Friday night in particular stood out: dinner with our next-door neighbour (planned), a drink with some new neighbours who popped by, and off to another boat for more drinks and a conversation late into the night (all unplanned).
It’s also wonderful to be able to call on neighbours for help, like when I dropped my keys into the 9 metre deep water. A new neighbour gladly lent me their ‘Sea Searcher’ magnet, which caught the keys first time! (I was almost disappointed that I didn’t haul up loads of sunken treasure in the process)
I suppose the only potential drawback is that neighbours fit into the same social category as family- you can’t really choose them, and it’s often hard to escape them. If you were a shy and retiring sort, you might find the regular socials a bit trying. You might also feel obliged to be sociable to someone you’d rather run away from.
Thankfully, I don’t feel any of the anxieties expressed above. In fact, I feel greatly blessed by my neighbours- they’re a great community. In particular, the many spontaneous things we share with our next-door neighbour (meals, cycle trips, episodes of Doctor Who) bring loads of fun into my life.
things that might have been otherwise 
at sherborne wharf in birmingham city centre, there’s just the same level of neighbourliness – & just the same number of people one wants to be neighbourly with!i wonder if some of the reason you get more of that kind of thing in boatyards / marinas is because there’s so much more opportunity to actually see people than just when leaving for work in the morning & coming home at night – like when emptying the toilet, fetching water, filling up with diesel, taking the bins out etc?also come the summer when it’s nice to sit outside, unlike normal houses you’re not separated from your neighbours by a 7ft high fence!