Houseboats / Boatlife / Canal Cruising / Mooring Chat / Boat Porn

If you are on a permanent mooring, then you get a water hookup or you go fill up water tanks as you empty the waste? If you are moving around then how often do tanks need filling/emptying?

Some moorings come with water, some do not. We used to fill out water tanks every two weeks. Your potential water tanks might be larger/smaller. You might use less water than a family of three, you might use more. Difficult to answer with any definates.

Are some waterways/canals narrower than others? Presumably so. Is there a site that can tell me where a boat of a particular length/width can go?

Yes some canals have narrow locks (about 7-8ft wide) which will limit your cruising if you're a wide beam. Also some canals have a max length due to limitations in the locks. A bit of googling should tell you what's what. I think Wikipedia might list the max lengths for the canal if you look up the specific page, e.g. https://en.wikipedia.org/wiki/Kennet_and_Avon_Canal

Do you need the full amount up front to buy a boat? ie you cant get a mortgage on a boat, right? Who pays for an out of water survey? The buyer or seller?

Marine mortgages exist - that's the limit of my knowledge about them though. The buyer pays for the survey same as when buying a house. You want the surveyor to be working for you, not the vendor!

Security. I see a lot of boats just on the side of the river/canal as opposed to in a secured marina/mooring. They look like they are unattended for days if not longer. Isnt there a risk of break-ins?

As with anything, there is a risk of crime. Obvious things like don't leave your generator on the deck with easy access make you less of a target, lock up your bikes properly, don't leave a laptop on show in the window... I think crime rates do tend to be lower on the canals but you hear about the odd incident.

Marine mortgages are hard to get. We got a loan for ours from Tescoids. Only 2.some-odd % Better than a mortgage, only 5 years too
Pretty much all marinas have water, as do permanent moorings, otherwise you have to move to water point. We fill up every 4 days or so. 260ish litre tank, 2 of us, shower once a day.
Wherever you are, you have to move to pump-out point. If you've got cassette you have to hoik them out and empty them. Elsan points available on the cut (though crt are closing many of them)
Consider composting bog. Or incinerating khazi, if you've got loadsa dorrah.
Break ins do happen, boats get untied and everybody, and his dog, thinks your boat (home) is public property.
We found out, the (very) hard way, that our 'narrow' boat, doesn't fit single gauge locks. Older boats tend to belly-out, something to check