When a ship is lost at sea its last position may be known, this all depends on was there an alarm signal sent (mayday) was the vessel using AIS (a tracking system) which course was the vessel on, where was it bound for and the big one what was the weather state.
now lets say a vessel is traveling due east and the sea is rough to very rough, the tidal flow is West Norwest and the weather is cyclonic 8 to gale 9. The vessel sends a distress signal at 08:00 and all contact is lost at 08:25 now the people that will look for that vessel could take over an hour to get to its last position, did it sink? could it hold station with its own power? which way would it drift or be towed by currents and winds?
If the vessel sank at what time did it sink? which direction was the vessel headed when it sank, what shape is the vessel, what type is the vessel. All these factors affect the outcome.
To say that everyone knows where the vessel is just can not be. The MCA & RNLI (for the UK) have the latest equipment available, AIS is new and shows the position, name, destination, speed etc to every vessel in the area that is using AIS which is a good thing, modern SART and ERIPB units alert stations around the globe on distressed vessels and sailors all good things. If a vessel with all this modern stuff goes down quickly or inverts,trapping every one and every thing all the modern technology in the world is of little or no use, even if a EPIRB floats to the surface it only signals ITS OWN position. (with luck survivors are close)
It has been known that a vessel was found 7 mile away from the last reported position and the hull was recorded as being pointing in the opposite direction to which the ship had been traveling.
When it is said that a vessel is lost it is not known where it is
I know I have dribbled on with this subject, though I feel I have good reasons as this is close to my heart. and I say no more.
