@Uncle Fred
For what it's worth, here is info on swell/wave size, wind speed, white caps etc
windwater.html
However, some white caps are not real problem in the southern Indian and southern seas generally. This article -
Malaysia Airlines MH370: Rescue expert Aaron Halstead describes challenges of southern Indian Ocean search for possible debris - ABC News (Australian Broadcasting Corporation) - gives a good account of the problem in relation to swell height, visibility and depth perception from the SAR point of view (aerial and from ship height).