He mentioned business visit (B-1) visa, which is much easier to get. Also, if you live in one of 35 countries that participate in Visa Waiver Program, you don't even need a visa for a short term visit. http://travel.state.gov/visa/temp/types/types_1262.html#2
You we will sleep on the boat and commute into work.
Being from the UK you get 90 days in the US, then you need to do a visa run out of the country and can then come back. I think as long as you are being paid by an non US business immigration don't mind.
Perhaps instead of a trip to Mexico or Canada a night on the boat would suffice?
Your residence and HQ is on a boat, but you can spend your days on mainland. If you're really into quick coffee meetings you can use one of those co-working spaces silicon valley has plenty of.
