de @Zutai Abunai
To keep your paradise look, to your 30m wave handling, you should try using a natural looking beach system, that will let your patrons enjoy the natural waves lapping on the sides, and when the time comes, you still have the safety you need. Even if you need to have an oddly shaped 30m high berm to your beaches, you can have tunnels lead through them, or have the berm made out of the structure of the island itself.
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Using this type of safety feature, would let you take full advantage of your coast lines, while keeping the structure safe. Though, this does work best for larger scaled constructions.
Outline a business case for a floating island, return on investment USD 1 of investment converts to USD 102 in floating assets.
Starting point floating marina