Buy this Baby (yes you recognise it) ($980K)
(very more luxurious than our days)
Autonomous Side Scan Sonar
4 Divers with deep diving capability
Underwater metal detectors for Divers
Portable Underwater Suction Dredge
Estimate spending maximum of $1.8 million (buy Takapu, hire major equipment, pay crew) for a possible $4,744,992 return if all gold is recovered. Should see 10 crew rewarded with even shares ($300k each)
Now I see all you matelots jumping at a chance of surveying Auckland Islands again. I AM!!
There will be Rum.