Every time these things are mentioned, I always wonder about that. Now that someone is building a modern equivalent (https://www.wigetworks.com), I wonder what they are doing about avoiding collisions.
Normal aircraft typically spend long periods in autopilot, whereas these things would presumably require a constantly vigilant pilot. And not just to avoid big ships, there are plenty of things floating in the ocean that could destroy one of these things: small boats, buoys, debris. The mast of a small sailing dinghy would be enough to cause a catastrophic crash.
I like the idea of this kind of craft, but I can't see it working at scale.
On the KM, the rear engines are the ones used in flight, and they're mounted well above the ground. The front engines are more of a booster to get it airborne, but they are indeed incredibly vulnerable.
You might be able to get it airborne without as much boost if you had the help of an intermediate phase of acceleration as a hydrofoil. The Orylonok uses a ski in this vein.
Normal aircraft typically spend long periods in autopilot, whereas these things would presumably require a constantly vigilant pilot. And not just to avoid big ships, there are plenty of things floating in the ocean that could destroy one of these things: small boats, buoys, debris. The mast of a small sailing dinghy would be enough to cause a catastrophic crash.
I like the idea of this kind of craft, but I can't see it working at scale.