.14 is 1:7.
You can estimate the wavelength by L=1.5 period squared. So ten seconds is 150 and the critical height is 21.4 m roughly 70 feet. That depends on the water being on the water being more than half the wave height deep.
If it were 5 seconds it would have a critical wave height of about 5.5 m.
Of more importance to you is that in shallower water waves slow down so decrease in wave length and increase in height and break at a depth of 1.3 height generally that will be approaching shore. So if the waves were 3 m they would break in 3.9 m a wave height and depth you would want to avoid, but usually evident by breaking waves.
A 5 m ocean swell is not a concern because the wavelength is long so the slope is more gradual. However in shallow water and against a current a smaller chop can be unpleasant because it is steeper and much closer.
Probably you want to look more at windspeed, water depth and current. You may set a limit of say 30 knots, which should be manageable provided it has not been blowing for some days over a long fetch and the water is reasonably deep. At that point you would probably be looking at storm jib and double reefing because you could expect higher gusts to say 45.
Last edited by chris_gee; 07-23-2007 at 07:50 PM.