Just for a change her is some information about an unusual design of seismic ship from Marin Teknikk. Two of these exist, and they were designed to engage in "4D" seismic where the fourth dimension is time. In order to carry out this function the ship lays a line of geophones on the seabed and then monitors the results. I don't know exactly how it works, but it is said that over time the ship is able to monitor the movement of hydrocarbons in the reservoir. Other vessels, not purpose built, are also used for this task as in the "Trinity II" accident in the Gulf of Mexico a while ago, when the Mermaid Vigilance was used for the job.

TYPE: MT 6007		NAME: BOA THALASSA		PHOTO: Jan Plug
GENERAL		PROPULSION		DECK EQUIP
Length OA	80.35 m	Engines	4 x Cat 3516B	Workdrum pull	-
Breadth	16.4 m	BHP	-	Capacity 1	-
DWT	3000 t	kW	-	Capacity 2
Deck area	-	For'd Thruster	-	Accommodatn	57
Fuel	-	Az Thruster	-	-	-
Pot water	-	Aft Aziprops	-	-	-
Mud	-	Bollard pull	-	Sharks Jaw	-
Base oil	-	DPII	-	Cranes	-
Brine	-	Joystick	-	Cranes	-
Dry bulk		Year built	2008	Shipyard	Fosen MV
Previous names	-
Comments	Seabed logging vessel