I am definitely not advocating large scale military invasion and occupation. The external power would take over a tiny bit of land - say 1000 km2 - to set up a city.

So, a small-scale military invasion and occupation??

The issue isn't land you will be taking over, the issue is people. Some of them (probably a lot) will not want your thalassocracy. Some of them (and in Yemen, pretty much all of them) will be adept with weapons.

without major political upheaval (e.g. revolution, war...

You want to come into the Middle East, set up an enclave completely different (politically, culturally, etc.) from anything around it and you don't expect war? Um, may I suggest you ask the Israelis about how well it works X-/