Can Ocean Waves Really Travel That Fast?

[starfire123]

A former sea captain recounts a stormy night in Atlantic when he observed waves with wavelengths of a few metres passing his 51m long ship in less than 3s. Should you believe him?

How do we go about answering this question? I have no idea where to start from, well, we learned about group velocity and phase speed of waves, but I don't know how to use them to answer the question?

 

[SteamKing]

Think about the vessel heading into the wave. If the vessel had some speed on it, would the observation about the waves make sense?

 

[starfire123]

hm.. i think its possible? because waves can travel at a speed of 1m/s (assuming wavelength is 3m and period=3s?)

is tat the way to support the answer though? it seems too simple

 

[SteamKing]

Don't you know a formula for calculating the velocity of a deep water wave given the wavelength? Remember, deep water waves of a given wavelength all travel at a certain velocity relative to a fixed reference point. An observer on a vessel is not necessarily fixed in position relative to the wave motion.