Mark, are you saying that you didn't get 12 months, or that someone at DOS told you that it was not possible to get 12 months?
Was your cruising permit issued for 12 months? Assuming you brought your boat in?
Cruising permit is for 12 months but the humans only get 6 months at a time and I haven't heard anyone getting 2 x 6 months in 12 months.
If I had heard of it then all the Australians would have 12 months in the USA in their cruising year, wouldn't they?
The USA is not unusual in doing this. In fact the USA is more liberal than most other countries.... EU 3 months in 6 months, same with Turkey, Thailand has changed to a similar thing where visa trips over the boarder no longer suffice. Indonesia is the same with a penalty of boat forfeiture!
So getting 6 months in a block is good! Getting 12 months is not being offered anywhere that I can readily think of. Nine months is great!
So with the USA if you do 6 months in on a B2 (of the B1/B2 visa) visa then you will need to go out for a reasonable amount of time, more than 10 days (I think it says 14 days) before you go back in.... But when you get back in I doubt you'll get a full 6 months... Perhaps more like three months to take your time in the USA to 9 months in 20 months.
The only way I can think of to try to squeeze the Americans would be to stay as long as you can, do a international trip, and then go for a visa extension when back in the USA pleading to wait for the end of Hurricane season (etc). That's fine if you get it, but if you don't get it you must leave immediately.
BTW the visa extension takes 6 weeks and during that time you can stay if your entry time has expired. So one shouldn't apply for it too early! But the what happens if you are declined?
As a final point, one should never piss off the Damn Yankees because the USA is so good for flying into and out of when cruising, particularly for Australians, particularly when cruising the Caribbean and Central and South America... So if one plays silly buggers with the USA Immigration laws and you get the big red DECLINED stamp in your passport not only can't you use the USA to fly through but many other countries won't like you either! Excepts, Venuzalea, Cuba, Iran and North Korea......