Ukdivers - Lesson plans

31. Nitrox Practical Skills

Key Points

No compulsory decompression to be incurred, hold stop depth, decompress horizontally, strict adherence to dive plan and records, obtain reflex reactions, ensure MOD not breached, get weight right, ensure depth is maintained whilst deploying DSMB and DSMB is inflated properly. Max PPO2 = 1.4
Note: Max bottom mix = EAN40, Max decompression mix = EAN50

Introduction

Brief (SEEDS)

E - Explain dive plan, mid-water DSMB deployment and regulator switching.

E - Full kit, Pony or twin set, DSMB/reel, good positioning of regulators and reels etc, complete dive slate.

S - Come up slowly in case of difficulty.

D - Get buddy to check the regulator prior to switching, ensure correct mix for depth, avoid entanglement of regulator whilst inflating DSMB. (Avoid freeflows use exhaled air if appropriate)

S - 'Go up and level off at 9m or 6m', 'you deploy DSMB', 'You check my regulator prior to switch'

Questions

Kit UP

Demonstrate, work in buddy pairs.

Buddy Check (BAR)

In buddy pairs. Check all regulators are functional

Entry

Demonstrate, mimic and correct.

Teaching subject (good positioning, demonstrate, mimic and correct)

Deep

Demonstrate gas switching with buddy checks - Students repeat
Demonstrate tying off reel and partially inflate - Students repeat
Whilst still tied off, demonstrate holding reel and DSMB with one hand and partially inflate DSMB with other - allow DSMB to ascent 1-2m - Students repeat
Ascend to approximately 2-3m off the sea bed and demonstrate mid-water deployment of delayed SMB - Students repeat
Ascent to 9m for 5 minutes, demonstrate horizontal positioning - Students repeat
Demonstrate gas switching with buddy checks - Students repeat x 4 (secure discarded reg.)
Ascent to 6m for 5 minutes - hold depth
Repeat 6 and 7, develop reflex actions
Ascend slowly to surface

Exit

De-Kit

Debrief (REAP)

R - Review - key points.

E - Encourage.

A - Assess - give constructive feedback.

P - Progression - link to next session.

Questions

Assessment Dive: Students create new dive plan and lead dive, must including mid-water DSMB deployment, 5 minute stops at 9 and 6m. Instructor to assess:: DSMB deployment skills; buoyancy and depth control during stops; deco stop time management; gas switching techniques, strict adherence to plan and completion of dive sheets, CNS%, UPTDs and tissue codes.