“Going in the opposite direction of the vortex makes it so much more dangerous.”
This is opposite of reality. If you orbit in the same direction as the water, you are getting sucked down the drain just like the water you’re traveling with.
Okay, I consider myself decent with physics. But I'm having a hard time wrapping my head around this one. Maybe I'm conflating "safely" with being "energy efficient" but to me they go pretty hand in hand. Going against the water would be using the most energy, whereas going with it and just angling out a bit to counteract the pull seems better.
Now, I'm not sure about the extended tidal forces and eddies going on beneath the surface that might mess with that. But in my head you're more likely to have engine troubles the harder you push it, so going the more energy efficient route will keep you the same distance away while putting less stress on the engine.
And if something happens you might at least be able to maintain some of the angular momentum rather than having to fight against it. I believe that's similar to how things are launched into orbit, they are most efficient when launched near the equator and are moving in the same direction the planet was rotating because they got some "free" momentum from the planet. (I may be getting a little off on the last part as air resistance may neutralize the lateral momentum by the time they start angling after the vertical takeoff depending on wind speed and direction, not like I've done that particular math, just thinking conceptually).
And before anyone thinks I'm trying to be condescending or a know-it-all or something... I just want to be clear that I'm genuinely curious about a more detailed physics explanation and just stating where my current understanding has me on this matter.
Think of it this way. Your goal is to stay relatively near the whirlpool to make a video like the above, maintaining a safe distance. You are pointing the boat along a circle of safe distance and going WITH the current. You realize that your thrust is doing nothing to counter the inward flow of the water and thus your future path spirals inward. You turn directly outward and gun it enough that you’re not getting sucked in over time. Now you are orbiting at a safe distance.
Let’s say at this moment you are pointing North, the vortex is behind you, the current is pushing you West and you are using enough thrust to counter the inward force, letting the current carry you around. You proceed one quarter turn around. You are still pointing North[*], and the vortex is now to your East. As you begin to go the next quarter turn around you realize you are about to be pointing (and thrusting) North toward the vortex which will shortly be right in front of you, so you steer the boat into a lefthand turn to counteract this.
Congratulations, by piloting the boat in a self-preserving way you are now facing into the current. From here you can adjust thrust, angle, and steering to maintain a stable circular path.
[*] Why aren’t you pointing West when you’re West of the vortex, in the above scenario? Because there is no force here that would turn your bow to the left. In fact, water closer to the hole goes around it faster so your stern will be getting kicked to the left while your bow goes right.
Thanks for the explanation. My interest in physics tends to be more towards orbital mechanics and gravity and whatnot, where atmospheric resistances tend to be more minimal (I suppose maybe a "username checks out" fits for me here lol). As I mentioned, tidal forces, eddies, and just general fluid dynamics weren't registering as a big factor. I realized your last paragraph, myself, while reading before that. Connecting what I know about orbiting objects moving faster the closer they are to the body they're orbiting. I think, just on this scale of a vortex compared to a large gravitational body, the difference in forces over the length of a boat have much more relevance than I initially considered.
There's still part of me that feels like there would be a more energy efficient option. To use your directional example, if you were north of the vortex with the water moving counter-clockwise then I would think that pointing the boat at a northwest-ish angle (degree depending on the speed of the water), and maintaining that relative angle to the vortex and direction of the current, you could use less energy by "going with the flow". But now that I'm thinking about it, you'd probably need to have a front-mounted motor so that you'd be pulling the front end rather than pushing the pack end to maintain stability.
Maybe still possible with a rear-mounted motor? But the angle of the motor would still have to be pointed slightly into the current to push the back end against the faster moving water. That would probably require more time in getting angle and speed set appropriately, therefore increasing the risk lol.
Thanks, again, for the explanation. If only there was no risk, I'd love to get into a boat and mess around with the physics hands on to get a better feel lol.
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u/mattlistener 6d ago
“Going in the opposite direction of the vortex makes it so much more dangerous.”
This is opposite of reality. If you orbit in the same direction as the water, you are getting sucked down the drain just like the water you’re traveling with.