Marine search will take months
Just looking at the marine AIS track of the search vessel 'XUE LONG' shows that she is doing 3 hour E-W tracks then side-stepping 3nm and doing W-E passes. All this at 12kts in seas chopped up by 26kt winds.
So to fully search an area of 600x600nm would take 10,000 hours or 417 days.
The underwater search will also be a slow process, as any underwater towed device will travel even slower.
A faster method would surely be a U2 type spy plane with high definition digital cameras... Do the Orions carry these cameras?