In the case of an aircraft since it's above you it visually decends down to the horizion at eye level. With a boat below you it visually rises up to the horizon as it approaches the vanishing point. This is convergence in action.
Can you see the problem here with claiming the boat sailed up, over and behind a curve three miles out? Say the aircraft is a helicopter shadowing the boat at low altitude.
911: "Fire, police or ambulance?"
Vod: "Hello, Coast Guard please!"
CG: "go ahead caller"
Vod: "I just witnessed a helicopter travel straight down into the ocean three miles out."
Vod: "It was following a boat that went up and over the curve!"
Vod: "The helicopter just went straight down, my god the humanity!"
Yeah there is always some perspective illusion to save your arguments. You just throw around a few words and you are done, your brain is happy, you tricked yourself yet again.
Tell me, why did PBS fake their proof that the Earth's surface has enough curve (24') at six miles to hide an entire helicopter in PBS Discovery Science Genius Episode 6? There's no reason to fake the proof unless it's actually flat. They used the same frame twice, one frame with a helicopter added via CGI. Why the fuck am I being fed hoaxed images if it's a globe? These fucking scammers are taking public funds and donations.
It's time to go fucking kill yourself, go find an oven and crawl inside. Don't forget to blow out the pilot light and turn on the gas first or you'll just cook yourself to death.
Will you pay to go to mars?