Diving Environment

1. Diving Environment

2. Objectives • Identify environmental conditions, which vary from region to region. • State the importance of an area orientation and list in order of preference three sources for obtaining an orientation. • Describe and discuss 4 effects of waves on a diver and describe techniques for dealing with each. • Name three common types of currents and describe techniques for dealing with each. • Describe how to get out of a current. • Discuss the effects of tides as they concern a diver. • Describe techniques for diving in kelp. • Describe the primary danger of rocks to divers, and three techniques for preventing injury. • State two primary factors affecting visibility and recommended techniques when diving in limited visibility.

3. Temperature • Thermocline • An abrupt change in temperature at depth • Do not confuse with an increase in cold due to suit compression

4. Temperature • Upwelling • Seasonal condition in CA • Caused by wind • Surface water is replaced by cold deep water. • Extremely cold from the surface to depth. • Extremely clean and clear. • Post Upwelling • Plankton blooms

5. Area Orientation • Importance • Protect you, marine life, environment • Enjoyable dive more likely • Sources for area orientation • Active instructor • This is your best source of information. • Active divemaster or dive guide • Experienced local divers

6. Kelp • General Techniques • Dive with a buddy • Move gently • Streamline gear • Save air • Pick path • Pay attention to navigation • Carry knife or shears • Kelp is easily broken or snapped by hand • You can bite through kelp

7. Waves • Primary cause • Wind • Strength of the wind • Distance the wind blows over water (fetch) • Duration (period of time the wind blows without interruption

8. Surge Wave energy felt on the bottom. • When wave size remains constant • depth increase surge will decrease. • Moves in a circular or elliptical pattern.

9. Surge ___________________________________

10. Surge • Do not fight the surge. • When surge is against you, hold on to rocks or kick to hold position. • When surge is with you, kick to make progress. • Surge is strongest toward shore. • Sand Transport

11. Surf Area of breaking waves near the beach • Waves break when the water depth becomes too shallow to support the wave General Techniques • Get through the surf zone as quickly as possible • Keep control of all equipment • Follow the last wave of the set • Choose an appropriate entry/exit technique

12. When in doubt about your ability to handle the waves and surf, DO NOT ATTEMPT THE DIVE!

13. Rocks Primary danger is slipping • Injury prevention • Wear protective clothing • Walk with care • Fend off • Fingertip diving • Be very aware of surge. • Pick a spot to place your hand and fend off prior to the surge pushing you into the rock. • If possible select a spot on the rock that is bare and not covered

14. Visibility • Factors which affect visibility • Turbidity • Particulate matter in the water • Light • Best time to dive is when sun is high in the sky • Run-off • Pollution • Wind • Tides • Waves, Surge and Surf

15. Limited Visibility Techniques • Good buddy techniques • Frequent checks • Physical contact • Positioning • Dive lights • Good buoyancy control • Avoid stirring up the bottom

16. Currents Near Shore • Rip Current • A current running directly away from shore. • As a general rule, it is advisable to avoid rip currents. • Choose entry and exit points that route you between the currents. • Identified by dirty mushroom shaped patches of water • Longshore • Current that runs parallel to the beach. • Often strongest within the surf zone

18. General Techniques for diving in current • Begin your dive against the flow of the current • Hug the bottom • Hold onto rocks or shelter in protected area

19. Finish your dive up-current from the boat • Allow for the effects of the current on air consumption • When beginning the dive against the current either • Go farther than normal before turning around or • Look for the anchor or exit point early Current X 3000 psi 1750 psi 500 psi

20. Getting out of a current • If a current is moving you in an undesirable direction, escape the current by swimming across the flow of the current • This applies especially to • Rip current • Longshore current

21. Other Currents • Standing Current • River or ocean currents • Require special training due to special hazards • Upwelling • Upwelling is considered a current although its effects on divers are limited to temperature considerations.

22. Tides • Daily rise and fall or ebb and flow of water • Can be predicted • Tide tables available through government and private agencies

23. Tides • Visibility • Best visibility is at high tide • Worst visibility is at low tide • Choose time to dive and dive site accordingly

24. Tides • Surf zone • Location of surf zone may vary with tide as depth of water changes • Intensity of surf zone may vary with tide • Currents • Tidal currents may be too strong to swim against • Develop local knowledge and knowledge of current diving

25. Marine Life • Smooth gentle movements will allow you to get closer to the marine life. • Abrupt, thrashing movements will frighten the animals away. • Most injuries associated with marine life are defensive actions on the part of the animal

26. Conservation • Local knowledge • Look but don’t touch • Buoyancy control • Fin control • Fish and game regulations • Body/gear awareness • Collect only appropriate items, at appropriate locations and times

27. No Collecting in Class!