1y ago

xkcd #2935: Ocean Loop

https://xkcd.com/2935

Alt text:

I can't believe they wouldn't even let me hold a vote among the passengers about whether to try the loop.

20 comments

Next try to calculate what it would actually mean to make that much water follow a path like that. My guess is, it’s going to get very spicy.
- The xkcd explained brushes near it.
  Many of the passengers would suffer extreme injuries from the changes of velocity (up to 230 mph based on a loop radius of 3 x ship length) and rotation (unlike rollercoasters, or even airplanes during simple take-off and landing, passengers aren't normally strapped down).
  
  Can't you just tell them to hold on to something?
https://explainxkcd.com/2935
Tales from the Loop
Sorrynotsorry, I've just got into watching it and it fit so... haha.
- Thanks, you just gave me something to watch :-)
  (Although I'll finish my current season of doctor who first)
How fast would the water have to be traveling for this to actually work? Pretty sure there was a waterslide built with a loop once and it infamously didn't work, but those work on gravity alone. With enough pressure it should be able to loop, right? Or would it just get wonky because it's a fluid? 🤔
I feel like this could be one of those things that works perfectly if you make a small model, but won't ever scale up due to reasons.
- I don't think he's done one with ocean liners but he did one with trains.
  
  I was actually more curious about the water itself and forgot we were even talking about a boat lol. Could you force that much through an open loop without it sloshing back inward?
- I feel like it'd need to go at super sonic speed.
- Could you get 3 cats to do what you want? Maybe. What about 300 million cats? Water is like a cat sometimes lol
  my self taught fluid dynamics knowledge AKA fuck fluid dynamics
Holy shit I wonder if it's even humanly possible to build one of these in the ocean for any size ship.
- Maybe something small, like a jetski…
  
  How about a duck
- You just have to go fast enough. The minimum speed keeping you from falling out of a circular loop is sqrt(gr), with gravitational acceleration g and loop radius r. 10m radius requires 36km/h, which might be suitable for a Jetski. Larger ships need bigger loops to physically fit, and consequently larger speeds. It's quite surprising, but a monstrous 100m radius loop needs less than 120km/h.
  
  so mass doesn't factor into the equation??? a Jetski made from aluminum would need the same speed as from osmium?
Maybe they're just on the Grand Line headed to the new world?
- With enough knock up power maybe we could reach the sky with this bad boy.

20 comments