One of the problems that can be encountered with scale models is not that of wave height, but of "real" wind speed, well found and waterproofed models (remember it is difficult to sink a boat without letting water in) you will sail in the scale waves that terrify full size ships.
If you are out for a sail and the wind is blowing your ears back, with strong and violent gusts, do not be surprised if the model lays over on its side or rocks alarmingly, To give you an idea of how it all equates we have included the following details.
REAL WIND SPEED TO A SCALE OF 1/96.
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KNOTS SCALE WIND SPEED FORCE OF THE WIND BY
BEAUFORT NOTATION = 1/96
.... ........ ...........
5 48.9 Force 10 gale
10 97.8 " 15 4th degree
hurricane
20 195.96 " never recorded
30 293.00 " Mach .4 ?
....... ........ ...................
You will be surprised how large the waves can be that your model will sail in, but remember, on the insides nothing must move, and on the outside all hatches and openings must be secure. If in doubt resort to a small elastic band running from the bottom of the hull to the underside of any lift off section. Flush hatches will benefit from a thin film of waterproof grease, ( babies bottom type) spread on to the mating surfaces, this is if you want to go out in really evil waters.
Happy Sailing.