Winter2016AlertDiver

WINTER 2016

Dive computers generally

work as designed, but the

mathematical algorithms

do not evaluate many of

the factors that can alter

the decompression risk of a

given exposure.

Opposite:

Bubbles can be

seen in a diver’s heart on

the screen of a portable

ultrasound device. The

right heart is shown on the

left side, with the right

ventricle above the right

atrium. Many of the bright

spots in the right heart are

decompression-induced

bubbles (in contrast with

the bubble-free left heart).

Bubbles are not found after

all dives but are more likely

after dives with greater

decompression stress.

imited gas supply and less-than-stellar

thermal protection once worked to cap

decompression stress for the typical

diver. Increased choices for gas supply

and improved thermal protection have

enabled divers to go further and longer.

Dive computers have likewise expanded the

freedom to explore. The square profiles of

the past can be replaced by complex dive

profiles that are easily tracked by these little boxes.

Decompression safety may be achieved by staying

within dive computer or dive table limits, but

decompression sickness (DCS) can develop even

after dives that remain within prescribed limits.

Dive computers generally work as designed, but the

mathematical algorithms do not evaluate many of the

factors that can alter the decompression risk of a given

exposure. Building in modest buffers at every step of

the diving process can help ensure good outcomes.

This article will discuss concepts important for

conservative practices, some of the pitfalls that must

be overcome, and practical strategies for defensive

dive-profile planning and implementation.

CONCEPTUAL CONTROL

Know the risks.

Diving is used for both work and

pleasure, and in the vast majority of cases it concludes

without problems. The risks, though, should not

be ignored. Understanding them is a critical step in

preparedness. Early recognition of issues can resolve

many before they become troublesome.

Take responsibility for your safety.

Do not give any

other person or any device complete authority over

your activity. Some divers will follow a divemaster

they just met without question; others will follow a

computer without thinking about what it does not

know or will expect it to get them out of trouble they

may create. Any person or device can make mistakes.

Make sure that you are actively and intentionally

involved in every step of every dive, able to lead

yourself when necessary.

DEFENSIVE DIVE PROFILE PLANNING

BY NEAL W. POLLOCK, PH.D.