Deep diving

Technical divers Kendall Raine, left, and John Walker prepare for a deep dive. (Bob Chamberlin / LAT)

Sept. 15, 2014 2:28 PM PT

A slow ascent to the surface ‘offgasses’ the tiny bubbles that can kill tech divers. But as they go deeper and deeper to explore ruins, they’re testing the limits of decompression.

In a moment of contemplation, technical diver Kendall Raine pauses before preparing for deep dive to recently discovered UB-88 submarine in the Catalina Channel. (Bob Chamberlin / LAT)

Technical diver Kendall Raine evens out the air in his dry suit. (Bob Chamberlin / LAT)

John Walker, left, sports 200 pounds of gear as he and fellow tech diver Kendall Raine, right, ready for their second encounter with a German submarine more than 230 feet below the oceans surface. The dives, Walker says, are quite serene. Besides bubbles, there are no sounds of engines, no people yakking in your ear. It is spectacular. (Bob Chamberlin / LAT)

Scott Brooks steps into the water to assist Johnny Walker and Kendall Raine. (Bob Chamberlin / LAT)

Fred Colburn is a support diver for Kendall Raine and John Walker (Kendall Raine / For the Times)

Technical divers Kendall Raine and John Walker ascend from a dive to recently located UB-88 submarine in the Catalina Channel. They were at the end of 80 minutes of decompression stops, slowly rising to the surface after spending 20 minutes on the bottom photographing the sunken ship. (Bob Chamberlin / lat)

Technical divers Kendall Raine and John Walker ascend from a dive to recently located UB-88 submarine in the Catalina Channel. (Bob Chamberlin / LAT)