4-5m swell in the southern ocean
It's not so much the swell that's a problem for searching but the sea and rain.
Swell in that area is usually generated by sub-polar lows or tropical cyclones to the North. It travels thousands of kilometres from origin. The weather at any mid-latitude is mostly unrelated to the swell.
In a previous career I monitored and reported on sea and swell in the Western Australian littoral - particularly off Perth and in the North-West.