I've noticed in several locations the statement that 100ft is the limit for SCUBA searches. Just wondering if that is a TIGHAR created safety limit or exactly what the origin is for that number. I know that one can reliably dive much deeper than that using the proper equipment and techniques.
Randy
The 100 ft limit is a self imposed TIGHAR limit for safety reasons. During some of the early expeditions there was some diving to deeper depths, but the risks were not well appreciated at that time, and might be considered reckless in hindsight. Since then, TIGHAR has since preferred to take a much more conservative approach. There is no reason to loose a live person searching for a dead one.
Yes, it is possible to reliably dive much deeper with proper equipment and techniques, but out at Niku there is no margin for error, zero. If we were to have a problem, the entire team and the ship would have to be expedited to the nearest evacuation site, Canton Island, some 24 hours away. As you will probably confirm, a 24 hour delay in treating a dive accident would likely be devastating if not fatal. TIGHAR is simply not willing to go there with volunteers, the consequences would simply be catastrophic for both a diver in distress and the organization.
I hope that helps put the dive operations in perspective.
Andrew