Here's a plot of a ship at anchor in Gage Roads, during the blow last night & today. Initially facing NW last night as the front built. A lot of back & forward as she surged with each passing squall. By now, swung to the SW with the breeze. She's either paid out extra chain, or had a spot of anchor drag. I trust they had a reliable anchor watch on duty!! ??
I didn't know you could get their anchor swing off Marine Traffic..
It looks like they all show a bigger radius once the wind backed to the SW though
Disagree, that ship DID not drag its anchor.
If I had the time I'd try and find one of my tracks where I did drag a bit [CQR] and my track is not an arch but falls back back from the original arch quit a lot in very erratic ways.
Select to expand quotenswsailor said..
Disagree, that ship DID not drag its anchor.
Yeah I agree it most likely wasn't dragging. I looked at all the boats tracking history after Poodles initial post and they all did the same when the wind swung. I also doubt they all had to lay out more chain.
Without going and looking at the the BoM history, maybe the wind speed picked up with the shift and the boats took up some of their slack (catenary I think may be the proper term).
Here's another one form the same time period (Sunday evening building NW?r swinging to SW on Monday morning). This is the big Maersk offshore support vessel, sitting a bit closer to shore of Cott beach. A naval artichoke mate of mine that works in the heavy marine industry was out sailing near her on Saturday. He reckons before the storm they were sitting on DP (not anchor) - This incurs a lower harbour charge. Cheeky buggers!! 
What on Earth is a 'naval artichoke' ?
And DP? (Diesel Power?)
In this case one should be fined for unnecessarily polluting the environment.
Dynamic positioning. The use of satellites to input engine controls to maintain a position. These ( Oilfield supply) vessels barely move more than a couple of feet when operating in this mode. Even more accurate when alongside an Oil rig or platform and that vessel hold a reflector that's the vessel reads with a rotating scanner.
these DP vessels usually have a number after their classification. I.E..DP3. This means 3 independent systems running concurrently to maximise positional stability.
In light weather the generator to keep the lights and systems running can power an azimuthing ( rotates in any direction) propellor that lowers hydraulically from amidships or thereabouts.. this reduces operating costs and prevents running up the hours on the main engines ( usually 4). As the weather picks up the Vessel either needs to start main engines to overcome the wind load or drop anchor. The DP system is a virtual anchor. Always two people on the bridge. These vessels are run by professionals. Australian Masters are highly regarded and skipper many of the Scandinavian vessels that dominate this industry. Ships are probably just straightening their chain. By the time the anchor line is taut you have uplift. Uplift is just prior to breakout ( that's how you break an anchor out when departing). Unlikely to be veering chain at the height of a blow. Would be done before.
tried to edit typo's but the iPad cursor is too stubborn.
Select to expand quotesirgallivant said..
What on Earth is a 'naval artichoke' ?
And DP? (Diesel Power?)
In this case one should be fined for unnecessarily polluting the environment.
OK, I'll say it, Double Penetration and Naval Architect I think
