[QUOTE=dsmith;37129]Hi Alf:
Would it be possible to orient the ROV so that the camera view we get would make a tilted object appear vertical? That would certainly make for a disoriented ROV operator but is it possible?
Its too bad we don’t have a guaranteed vertical object beside the BOP to use as a reference point.[/QUOTE]
yes it is possible to be off from vertical/horizontal… I incorrectly call it pilot error… but in fact everyone who does it will get slightly different results.
When an ROV is working or moving it needs some kind of reference to vertical/horizontal. The pilot’s only view to the outside world is via cameras. These cameras need a reference point. ideally something fixed to the seabed.
In addition, the pilot needs to know where his ROV is relative to what he’s looking at, hence the quick camera movements up/down/left/right to verify the camera view relative to fixed vertical/horizontal points on the ROV.
Normally, there would be a [B]minimum[/B] of 4x bullseyes used: 1 on the 36" wellhead, 1 on the main frame of the BOP, 1 on the LMRP and 1 on the flex joint. These are installed from day 1 so to speak and monitored regularly with the ROV. Changes in readings are easy to see.
The ROV should be flying pretty close to horizontal although currents and other things can affect it.