No, generally speaking, waves pass underneath a floating object in practically all circumstances. You may feel like there’s a forward surge when a wave comes in from behind, but all forward momentum gained while sliding down the wave is lost once the wave peak has overtaken you and you’re climbing back up the wave. Basically, waves will induce a circular motion on a floating object.
There’s ways to trick and gain forward speed from waves, by basically picking a wave that’s high enough and continually sliding down on the front - Surfers for example. But that only works if your object is substantially smaller than the wave in question - which is sort of impossible for ships.
A boat can start surfing once the waterline fits on one face of a wave, so <1/2 wavelength. So a 70m tug just needs a 200m long wave. Mind you, those waves could be 30m tall and breaking over you :-O. So not impossible, but I'm not eager to try it.
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No, generally speaking, waves pass underneath a floating object in practically all circumstances. You may feel like there’s a forward surge when a wave comes in from behind, but all forward momentum gained while sliding down the wave is lost once the wave peak has overtaken you and you’re climbing back up the wave. Basically, waves will induce a circular motion on a floating object.
There’s ways to trick and gain forward speed from waves, by basically picking a wave that’s high enough and continually sliding down on the front - Surfers for example. But that only works if your object is substantially smaller than the wave in question - which is sort of impossible for ships.
Nice explanation.
A boat can start surfing once the waterline fits on one face of a wave, so <1/2 wavelength. So a 70m tug just needs a 200m long wave. Mind you, those waves could be 30m tall and breaking over you :-O. So not impossible, but I'm not eager to try it.
https://www.passagemaker.com/lifestyle/freaks-of-nature-rogu...
The wave-glider is much more practical.
https://www.liquid-robotics.com/wave-glider/how-it-works/
Thank you for such a thoughtful response.
Second order wave effects can cause drifting also.