I guess you might be able to get around this problem if the vehicle can take off and land on a land based airstrip and then stay at 10m over the water. Otherwise that is a crippling limitation since you not only need the ocean to be relatively calm when taking off, but also when landing.

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rbanffy 2 hours ago | parent [-]

Usually these planes take off and land on rivers, bays, and other protected shores with few waves.

	▲	datadrivenangel an hour ago \| parent [-]
		For FAA purposes this is 100% not a plane. Regulatory arbitrage is part of the value.