Night and Limited Visibility and the Divemaster

Main Points

• Motivation for diving

• Pre-dive Planning

• Equipment

• Dive Techniques

• Communications

• Hazards

Objectives

• Identify various reasons for participating in night dive and discuss implications for the dive master.

• List and discuss 5 considerations for pre-dive planning and safety.

• Compare day-time versus night-time diving equipment requirements for both the diver and the dive master.

• Discuss considerations for light etiquette and techniques, navigation, air management and ascent and descents while night diving.

Objectives Continued

• Describe various means of communication for diver-to-diver, diver-to-divemaster, divemaster-to-diver, divemaster-to-staff and staff-to-divemaster communication.

Motivation for Night Diving

• Determine diver motivations and objectives prior to the dive. – New experience– Adventure– Marine Life– Peer pressure– Included in the package

• Be prepared to deal with:– Stress – Anxiety– Excitement

• One option is to start the dive at dusk and allow the divers to become accustomed to the site, conditions and darkness as the dive progresses.

Pre Dive Planning and Safety

• Site Selection– Dive a known site.

• Day time reconnaissance is preferred.– Depth

• Consider earlier dive activities and N2 loading– Entry, Exit and Surface Swim

• Consider earlier dive activities for energy level of the divers

• Physical condition of diver – N2 loading / alcohol / fatigue

• Rendezvous at a well lit site– Or bring lights

• E.M.S. access.– Can be difficult to find you at night

• May be necessary to mark the spot

• Site assessment– Ideally conducted while there is enough light to see the site and conditions

Equipment:

• Diver equipment– Lights

• Primary• Back up

– What is the purpose of the back up?– When should the dive be aborted?

• Personal ID light – Standard minimum scuba gear

• Divemaster Equipment– Standard minimum scuba gear– Lights

• Lights to mark staging area• Lights to mark entry / exit points

– establish a range• Lights to mark surface platform

– Float or boat» Dive signal = red-white-red

– Anchor or bottom line

– Spare surface float with light attached• Rally point and working platform

– Recall system

Dive Techniques:• Light Techniques and Etiquette

– Turn on light before entering water– Signals

• OK• Attention• Distress

– Don't blind your buddy• Control your lights during ascent and descent• Be aware of reflection when checking gauges

– Don’t blind yourself• Be aware of reflection when checking gauges • Look into soft outer edge of beam

• Navigation – May not cover as much ground as day-time.– Check compass more often than day time

• Don’t have the same visual clues as daytime– Recognize the silhouette of the shoreline or boat

• Air management – Rule of 1/3 may be more appropriate then rule of ½

• Descents/ Ascents– Use lines when possible– Shine light in direction of travel– Pay close attention to depth and speed

Communications• Diver-to-diver

– Light signals – Touch

• Diver-to-Divemaster– Lights – Whistles

• Divemaster-to-Diver– Lights– Whistles/audible alarm– Megaphone

• Divemaster-to-Staff and Staff-to-Divemaster– Lights– Whistles/audible alarm– Megaphone– Cell phone/radio

Night Diving Hazards

• Disorientation– Use bubble trails– Establish reference point

• Buddy separation– More likely at night/limited visibility– On surface hold ID light arms length above the water

• Make sure to turn through 360 degrees

• Buddy exchange– Mark buddy teams or groups

• Marine life– Attracted by light

• Overhead obstructions– May not be aware you no longer have direct ascent to the

surface

Main Points

• Motivation for diving

• Pre-dive Planning

• Equipment

• Dive Techniques

• Communications

• Hazards

Objectives

• Identify various reasons for participating in night dive and discuss implications for the dive master.

• List and discuss 5 considerations for pre-dive planning and safety.

• Compare day-time versus night-time diving equipment requirements for both the diver and the dive master.

• Discuss considerations for light etiquette and techniques, navigation, air management and ascent and descents while night diving.

Objectives Continued

• Describe various means of communication for diver-to-diver, diver-to-divemaster, divemaster-to-diver, divemaster-to-staff and staff-to-divemaster communication.

Summary

• People night dive for various reasons.– Understanding those motivations will make

your job easier and help you provide a better experience for your clients.

• Proper use of briefings to communicate night diving techniques and etiquette will also result in a better experience for your clients.