Snorkelling&Diving

1. Generally via ladder
   1. weightbelt to buddy or help
      1. fins next
         1. ALWAYS keep mask on until out

1. ladder
   1. mask on
   2. fins on in water
      1. signal 'OK' once in water
2. Stride
   1. 'walking off a plank'
   2. all equiptment on (snorkel)
   3. right hand on weightbelt
      1. also holding computer down
   4. left hand holding mask on

1. shallow water blackout

1. take deep breath (only 1)
   1. bend at the wast and kick legs. Allow weight of legs to provide momentum
      1. Begin equalisation immediately
         1. Swim horizontally parrallel to the floor

1. look up and point
   1. turn in a slow 360 degree movement

1. breath quick and blow air out
   1. on surface

1. tilt head back (snorkel face the bottom)
   1. at surface air will displace water
      1. The rest can be blown out

1. attempted exhalation against the closed nose and mouth

1. dont store in box or sealed
   1. will cause mold to grow

1. Before
   1. re-lube and seal
      1. place in box of freshwater - ensure no bubbles
         1. pass into water seperately -dont jump with it
2. after
   1. No temperature diffs
   2. let soak in water over night
   3. Dry before take apart

1. AKA pre dive saftey check

1. wear wetsuit
   1. dry suit?

1. hypothermia
2. uncomfortable dive

Annotations:

• Light enters the eye through the cornea which with the lends focuses the image on the retina where it is then transferred to the brain via the optic nerve.

1. focus takes place

1. adjusts amount of light that enters

1. size changes when iris relaxes or tenses

1. Secondary mechanism to focus after cornea
2. adjusts amount focus the light image requires

1. maintain eye shape
2. clear pathway for light b/w lens to retina

1. signals produced by retina travel to brain

1. water slows peed at which light travels
2. change in speed causes light rays to bend
3. Refraction through diving mask
   1. affects close vision
      1. Therefore hand eye coordinations
4. How does dive mask help?
   1. Places a pocket of air b/w water&eyes.
      1. Light rays are refracted twice
         1. Clearer image focused on retina
            1. may now appear 25% larger
5. Color
   1. Red first blue last

      Annotations:

      • This is due to water absorbing light according to its wavelength

1. Pinna
   1. External.
   2. Collects/funnels sound&route to canal
   3. issue- sunburn
2. Ear Drum
   1. Tympanic membrane
   2. converts/transfers vibrations to energy
   3. across ear canal
   4. issues- burst under pressure
      1. equalise effectively
3. Ear Ossicles
   1. 3 small bones
      1. hammar
      2. anvil
      3. Stirrip
   2. middle
   3. help boost vibrations from ear drum
4. Oval Window
   1. Links ossicles to cochlea
   2. pick up vibrations from ossicles to cochlea fluid
5. Round window
   1. Seperates the middle ear and coclea
   2. Helps balance out pressure within cochlea
6. Cochlea
   1. fluid chamber
   2. changes vibrations into electromagnetic impulses
7. Organ of Corti
   1. Transfer of vibrations to electromagnetic impulse from tiny hair cells
8. auditory nerve
   1. Transfers impulses to the brain

1. used for equalisation
2. drains muscus from the middle ear
3. various methods of ear clearing
   1. yawning
   2. swallowing
   3. intentionally open the tube and equalise pressure
4. Pressure difference can cause
   1. temporary hearing loss

1. not enough weights
2. to combat - add weights
   1. and deflate BCD
3. above water

1. too much weight
2. sinking
3. inflate BCD
4. add weights

1. weight = upthrust
   1. pefect for snorkelling or diving

Annotations:

• If W1is hte initial weight of an object and W2 is the weight of that object when placed in water then the loss in weight is given by this equation

Annotations:

• Increase volume, increase buoynacy

Annotations:

• Small volume, lots of weight

Annotations:

• decrease volume (of lungs) due to the atomospheric pressure

1. L-R stands for Lloyds Register

1. as pressure increases. the volume of air occupies, also decreases
2. P1 V1=P2 V2
   1. p= pressure
   2. v = volume

1. swelling of the middle ear

   Annotations:

   • feeling of fullness Sounds appear "muffled" Blood - small amounts coming from the mouth and nose.
2. ear ruptures

   Annotations:

   • sudden relief of pain diziness and vertigo nausea and vomiting momentary unconsciencessness 
3. Round window ruptures

   Annotations:

   • Vertigo nausea ringing in the ears (tinnitis)  loss of hearing 
4. Treatment
   1. equalise
   2. ascend if pain is present
   3. dont dive when congested
   4. control descentg

1. quick descent without exhalation
   1. ambient pressure increases, the negative pressure becomes greater in the mask.
      1. causes tissues of face under mask to swell
2. have a mask that fits
   1. exhale into mask on descent
      1. never use goggles
3. treatment - remove mask

1. congestion, sinus and nasal inflammation or growths in nasal passage may prevent the exchange of air between the nose and the sinus'
2. signs
   1. pressure progresses into pain
   2. headache
   3. bloody nose & blood in mucus and spit
3. Treatment
   1. equalise
   2. abort dive if cant equalise
   3. dont dive congested

1. density =mass/volume
2. mass = density x volume
3. volume = density x mass