Look at the water using the Beufort Scale, it's very easy to judge the windspeed, there is no breaking or even frothing of the water which will start at about 10 kts wind speed. There is barely a 6" wave on a 6' swell with the only white water being a very small frothing on the ships wake. The ships speed is easily judged by the wake it is leaving (or in this case, barely leaving) Figure by the beam, configuration, and helo in use, this is a stern trawler of about 180-210' with close to 22' of draft when down to the Plimsol mark which would leave her wake at 13 kts which will be he max speed, standing at about a 5-6' breaking cresting wave and you'd see a long white frothy trail behind the boat from the prop wash. He's running between clutch and 1/3 ahead speed which will be between 6 and 8 kts to maintain steerageway, taking the seas 2 points off the bow, which is SOP. Another clue as to sea state is watching the guys walking and standing on deck, that's NOT what you see in rough seas. No, the sea state wasn't the problem here, the helo was hung on something that came loose suddenly. It's also the reason I don't allow helo ops off a cargo net or in fact, any clutter, cables, straps... to be present on the flight ops deck during operations. On boats rigged for heavy weather helo ops, we have a high speed winch in the center of the flight deck that we latch to the cargo hook on the helo and yank them down while the pilot works against the teather. It's very dicey operations and we tend only to use it in extreme emergencies.
