Extracted from some comments I sent elsewhere, on the subject of dealing with disasters by gettting a boat and using it as a bug out vehicle:

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My inlaws had a 46' Dolphin Catamaran for a while.  This is, in current dollars, a near million dollar, state of the art boat, with sails, diesel engines, GPS, auto-pilot, radios, staterooms, the works.

I've got moderate experience in several types of boats, from pocket fishing types to speed boats and small sport sailboats.

They were constantly having to replace "canvas" (usually nylon, fiberglass or kevlar on boats these days), lines, electronics and do engine work.  Nearly every letter from aboard was about the latest round of maintenance, the need for safety lines while at sea (including a man overboard incident), rough weather, mechanical failures at sea, keeping watch during such problems.

Pontoons are a catamaran, and almost proof against swamping, unless shot full of holes, though that is fairly easy to do.  As I've noted previously, there's no cover nor concealment on open water.

Small boats carry almost nothing.

Large boats carry a lot less than many people think.

Unless one has a classic 18th Century wooden pinnace, with crew, including carpenters, maintenance is expensive, time consuming, and takes tools or a port.  On second thought, it does even then.

Life on a boat is not some happy-go-carefree existence of drifting along watching the lesser castes starve.  It requires, if anything, more work than a landed lifestyle.  If it was so cheap and easy, more people would do it.

If one has a definite bug out destination in mind, a boat would certainly be ONE means to consider.  It is not, however, the solution to any other problem.  It is a hole in the water that one must pour money into to maintain, even when not in use. That money can better be spent on beans, bullets and band aids, a chunk of land, tools, etc.

Like the "get a light plane and pilot's license" threads on this forum a few years ago, there's much more involved than a casual glance suggests, and I believe even experienced boat owners are underestimating what's involved. 

I'd like to see comment on this subject from experienced Naval boat and ship handlers.  I suspect they'll be a lot less sanguine than many readers.