Ships holding station in mid-ocean

[Naga Sadow]

OK, if a ship has to hold station over a continental shelf, then OK, it can drop an anchor.

What about if they need to hold station over the main basin of the ocean (miles deep)?

I assume they would need to use the engines for this.. does someone need to stay at the helm, continually watching the ship's position and applying thrust to counter drift when nescesary, or is there some sort of sat-nav controlled autopilot that can just be set so that the ship automatically applies thrust when needed to hold station?

[Apogee]

ships always maintain someone on deck when at sea.

But you could use a sea anchor (basically a big ass bag that slows your drift) while at sea.

[Pille1234]

Ships can use the anchor in deep water too. The weight of the sea anchor and the chain holds the ship on position, as long as theres no storm or strong water stream. As scuba said, there's always an anchor watch on station.

[Bama_Operator]

When ships have to hold a position over open (deep) waters, they use either a DPS-1, DPS-2, or DPS-3 system to hold position which incorporates the main engines, stern & bow thrusters, and the rudders. HARDLY ever do vessels use anchors to hold position unless they have nothing else to use and they are in an emergency situation. Too many pipelines and cable transits all over the place now.

Frank L Beier/Beier Radio/ Techsol are one of the systems that are in use, and are heavily favored by the offshore petroleum industry. If you have any further questions, just let me know

[Argyll]

Bama beat me too it!

They have Bow and stern thrusters linked to the GPS sytem that enable the ship to stay exactly in a pre arranged Lat and Long

[Pille1234]

That may be true for oil platforms or special purpose ships, which need to hold position exactly.
Most military ships don't even have stern/bow thrusters to start with.

[Marmot1]

I wonder how they put those cables on bottom of sea.. there is i.e. big rift at bottom of atlantic which is highly seismic active not to mention numerous volcanos etc,