Hate to be a party-pooper, but all vessels need regular dry-docking.
1) Otherwise it's doomed to sink, eventually.
2) Or for other reasons. Even if decided to go completely hydroponic, no-materials-wasted, salt from saltwater, fresh water from rectification, solar energy, et cetera - you would still have to dock, since mechanical parts wear down.
The scientologists, for one fancy example, have asbestos on their "Freewinds", so they had to land.
3) Which brings us to another issue. An undesirable vessel, say bearing some political cargo, is usually deemed "pirate". That's the only thing pirates really were, in fact - official undesirables. (Well, okay, and criminals, too.)
That's to talk about vessels, leave alone arm-bearing ships. (Or "potentially bearing".) Most countries with navies have signed pirate eradication treaties.
And if you're a pirate, you can't dock anywhere.
This here passage was just a reminder on the possibilities of being framed.
4) Vessels need some higly-qualified personnel, like mechanics, a coxswain (a stuhrman), etc.. Altough, yeah, there are probably wogs in the navy.
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Those aren't the main reasons, though. My cynicism walks with that of Sci's, see. It said, I can't just poop and leave.
So here's some random site:
http://commercial.apolloduck.com/And it has
this Troops Transporter: "up to 40 soldiers", a rat packer, no space for anything, relatively cheap. 40 wogs could buy it for sure, even if with saving up.
Fact is, many have families, so this one's not any good.
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