Upvote:7
Normally, US citizens can only visit without a visa for no more than six months. Some countries allow visitors to apply for a visa to stay for longer. However, that does not appear to be true for the UK. From Standard Visitor visa:
How long you can stay
You can usually stay in the UK for up to 6 months.
You might be able to stay for longer if:
- youβre coming to the UK for private medical treatment - up to 11 months
- youβre an academic on sabbatical and coming to the UK for research - you, your spouse or civil partner may be able to stay for up to 12 months
Staying for 10 to 12 months is outside what is permitted under a Standard Visitor visa. As far as I am aware, there is no other visa that would permit tourism activities for more than six months.
Although US citizens do not need a visa for visits up to six months, you will still be interviewed by an immigration officer (ECO, Entry Clearance Officer). They do have the power to refuse entry to you if they believe you are arriving to live in the UK (and if you say "live-aboard cruising boat" that sure sounds like you intend to live in the UK).