unit 2- diving equipment

8/3/2019 Unit 2- Diving Equipment

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Unit 2: Diving Equipment

n Basic equipment.

n Scuba cylinders.

n Scuba regulators.

n Diving instruments.

n Buoyancy compensators.

n Weighting systems.

n Diving suits.

nAccessory equipment.

Instructor Materials: Teaching notes, various pieces of equipment and

models. Better yet, arrange to give the presentation on the sales floor of a dive

store.

INTRODUCTION

Attention Step: As previously stated scuba diving is an adventure sport. It is

also an equipment dependent activity. Without the right equipment you are

like a fish out of water.

Importance of Value: Scuba diving depends on our ability to adapt to an

alien environment with the help of specialized equipment. Understanding how

to use and care for scuba equipment increases the fun and protects your

investment.

Main Points: See presentation slides.

Student Materials and Conduct: Note taking material, student book kit, and

your undivided attention

Body: See presentation slides.

Unit 2- Diving Environment- Inst Notes


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n List the basic equipment you need to go skin diving.

n Describe scuba cylinders, including types and sizes, valves,maintenance, and inspections.

n Describe regulators and the equipment usually attached to theregulator.

n List the different types of diving instruments.

n Describe the types of buoyancy control devices and how toselect one that meets your needs.

n Describe the use of weighting systems.

n List the different types of diving suits used for warmth and

protection and describe how to choose the right suit for yourdiving conditions.

n List the accessory equipment that makes diving more enjoyable.

St udent Perform ance:By the end of the lesson students will be able to:

Performance Statement:

Describe to the students what will be expected of them by the end of this

lesson, and to what degree.



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Buying Equipment for DivingThere are several reasons to go to a specialized retail er such asa NAUI dive store.

n You can see and wear gear before you buy.

n Scuba retailers can help you with adjusting

the equipment.

n Scuba retailers provide instruction for

specialized gear.

n Scuba retailers usually service equipment.

n Scuba retailers rent equipment.

n Scuba retailers are your source for scubacylinder fills and last minute required items.

There are several reasons why you should buy your gear from a specialized

retailer, such as a NAUI affiliated dive store. These include:

You can see and wear the equipment in the store before you buy it and possibly

even try out similar rental items in the store pool.

Your local retailer is able to help you adjust items such as buoyancy

compensators (BCs) and to measure you properly for custom-tailored wetsuits.

Local retailers can provide you with the instruction needed when you purchase a

specialized piece of gear, such as a dive computer, video housing, or dry suit.

Your local retailer is usually able to service any gear that you buy at their shop.

Local retailers might rent or loan you equipment while yours is in the shop forrepair.

Your local retailer is your only source for scuba cylinder fills and last minute

required items.

Develop a good relationship with your local diving retailer. The salespeople there

will be able to help you select the right type of gear for localdiving conditions and

for your personal diving interests.



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Basic Personal EquipmentComfort and Fit are extremely important!

n Mask

n Snorkel

n Booties

n Fins

n Gloves

Because you wear most pieces of dive gear directly on your body, the comfort

and fit of each item is extremely important.



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MasksEnables you to see underw ater objects clearly.

n The most important consideration is

the mask fits your face.

n Some of the features of masks are

essential:

n There are many optional features.

Some include:

If you have ever opened your eyes under water without a mask, you know that

it is impossible to see clearly. This is because our eyes are designed to focus

in air. A scuba mask places a layer of air between your eyes and the water,

enabling you to see underwater objects clearly.

The most important consideration when you select a mask is whether the

mask fits your face. To check for fit: Place the mask gently against your face

without putting the strap over your head. Inhale briefly through your nose and

hold your breath, the mask should stick on your face.

Essential features include: A tempered glass lens to help resist breaking and

avoid injury if the lens breaks. A solid frame to hold the lens in position. An

adjustable, split headstrap that fits over a wide portion of your head. The

ability to block off your nose to help equalize the pressure in your ears. A

double feathered edge seal to help the mask fit to your face.

Some popular optional features include: Side windows to provide a wider

field of vision. A purge valve to help clear water from the mask. A low-

volume mask that fits closely to your face to give you a wider angle of vision.

It is also easier to clear of water. Prescription lenses.



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New MasksThe lenses are covered wit h a thin film of lubricant.

n You can use toothpaste to remove this lubricant.

n Washing w ith toothpaste helps prevent the mask

from fogging.

n Each t ime you don your mask you wil l need to

prepare it.

New mask lenses are covered with a thin film of lubricant.

You can use toothpaste to remove this lubricant by using the following

procedure: Put a little toothpaste on the inside of each lens of the mask. Rub

the toothpaste over the entire lens with your fingers or a soft, wet cloth. Rinsewell with fresh water

Each time you don your mask you will needed to prepare it. The most

common way to prevent fogging used to be to spit in the mask, rub the saliva

on the lens, and then rinse the mask. An alternative is to use commercially

available anti-fog sprays, drops, or creams.



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SnorkelsThe snorkel enables you to breathe normally w hile you

watch the beauty beneath you.

n There are many differen t features:

n Features that can be added:

Have you ever noticed that you can lie face down on the surface of the water

and float completely motionless? Its easy, and most people cando it.

However, every time you need to breathe, you must lift your head out of the

water and that takes exertion and gets tiring. A snorkel is the answer to this

problem.

There are many different features:

The basic snorkel is a J shaped tube with a mouthpiece at the curved end.

Other features that can be added to the basic snorkel include:

Flexible hosing to enable the snorkel to fit comfortably in your mouth.

A purge valve to allow water to drain out of the bottom of the tube.

A swivel mouthpiece so you can adjust the mouthpiece in your mouth and

swivel it out of the way when you switch to a regulator.

Baffles at the top of the J tube to keep water from getting into the snorkel at

the surface.

A molded or soft mouthpiece for added comfort.



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Select ing a Snorkel

Snorkels have both essential and optional features.

n The two most important

things to consider:

n Other considerations:

The two most important things to consider when selecting your snorkel are

comfort and breathing ease.

Other considerations:

The mouthpiece must fit comfortably in your mouth and should not be twistedwhen you place the tube or barrel of the snorkel over your left ear.

The snorkel itself should be between 30 and 35 centimeters (12 and 14 inches)

in length.

The inside diameter of the snorkel should be no less than 2 cent imeters (

inch). If the diameter is too small, it is like breathing through a straw.



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Booties

Booties provide protection and w armth for your feet.

n Booties are made from neoprene rubber.

n Some of the different types of booties you

can find are:

n The bootie should fit snugly but comfortably

on your foot.

Some of the different types of booties you can find are:

Slip-on 3 millimeter (1/8 inch) booties that come up to your ankle fo r warm-

water diving. Booties with zippers that come up over your ankle. The zipper

should have a backing to prevent water from entering directly through thezipper and to keep the zipper from rubbing your skin.

The bootie should fit snugly but comfortably on your foot. If it is too large

for your foot, you will have a lot of water transfer in and out of your bootie

during a dive and your foot will get cold. The excess room might also prevent

your fin from fitting properly or make it loose enough to come off.



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Fins

Fins provide the way to m ove yourself through the w ater.

n There are two basic types of fins:

n Size of the fin determines:

n Choose a fin that fits snugly without:

n If you are using fins tha t require booties, be

sure to try them on at the same time.

There are two basic types of fins: full-footfins and heel-strap fins. Full-foot

fins are typically used for snorkeling and in warm water.

Heel-strap fins also have a foot pocket, but the back of the pocket is open and

an adjustable strap goes across the opening. You must wear booties with heel-strap fins to protect your feet from blisters. You can use heel-strap fins for

diving in any temperature water.

The size of the fin determines the size of the foot-pocket and the blade length

and width. The blade of the fin is the flat portion that extends away from the

foot pocket.

You must choose a fin that fits snugly to your foot without cramping your

toes or pinching your feet

Some fins come with a plastic insert in each foot pocket. The insert helps

maintain the shape of the foot pocket when your foot is not in the pocket. You

should keep the inserts in the foot pockets whenever you store your fins.



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GlovesGloves provide protection and w armth for your hands.

n Your gloves shoul d fit snugly

and al low you to move your

fingers easily.

n You must be able to handle your

equipment while w earing

gloves.

n Be environmental ly conscious!

Your gloves should fit snugly and allow you to move your fingers easily.

You must be able to handle your equipment while wearing gloves. Your

instructor might have you wear gloves during your confined water training soyou learn how to work while wearing gloves.

You should not touch or handle the creatures you find under water just

because your gloves are protecting you from the environment. In many cases,

you can hurt or kill plants or animals just by touching them.



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Floatat ion DeviceDivers should wear some kind of personal floatation devicefor snorkeling or skin diving.

n The most commonly used is

an inflatable vest.

The most commonly used piece of flotationequipment is an inflatable vest

that is worn on the chest and is usually referred to as a skin diving or

snorkeling vest . The vest is designed to slip over your head and fasten at your

waist with a strap. Most vests of this design also have some type of oral

inflation tube.



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MaintenanceMainta ining your basic gear is simple.

n You should rinse your gear with fresh wa ter

after every diving day.

n Do not leave the gear in direct sunlight.

n Mak e sure your gear is dry before storing it

away.

n Inspect the gear regularly, especially before

a dive trip.

At the end of a diving trip, soak your gear overnight in fresh water and then

rinse it thoroughly with fresh water.

Make sure the gear is dry before you store it in a cool, dry area, like a

closet. For extra protection, you can store your dry gear in a sealed, plasticbag.

No matter how well you maintain your gear, you will need to replace some

parts periodically. Fin straps, mask straps, and snorkel keepers wear out.



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Review on Basic EquipmentWhat have you learned so far?

n What are the two most important features for the

selection of your basic equipment?

n What is one feature not essential in a dive mask?

n What are three factors that can reduce the ease or

efficiency of breathing through a snorkel?

Summarize this section

Review the main points of each slide:

Emphasis key points of each main point.

State the objective statements as questions .



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Scuba Cyl indersScuba cylinders allow you to store large amounts of air in asmall place.

n Scuba cyl inders are also know n as

bottles or tanks.

n They are regulated by:

Department of Transportation (DOT) inthe USA

Canadian Transport Commission (CTC)in Canada

n The air in a scuba cylinder is highlycompressed:

The pressure ranges from 120 bar

(1800 psi) to 310 bar (4500 psi)

Every country can be expected to have standards regulating scuba cylinders.

In the United States, cylinders are regulated by the Department of

Transportation (DOT) and must be inspected according to government

standards. In Canada, cylinders are regulated by the Canadian Transport

Commission (CTC), which has standards similar to the United States

Department of Transportation.



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Scuba Cyl indersMost cylinders are made of aluminum or steel.

n Aluminum Cylinders.

n Steel Cylinders.

The pressure of cylinders ranges from 120 BAR (1800pounds per square inch

(psi)) to 310 BAR (4500 psi). One BAR is equal to approximately 14.7 psi or

1 atmosphere (ATM). Most cylinders are made of aluminum or steel.

Aluminum cylinders do not rust, which is an advantage over steel cylinders.However, aluminum cylinders are more easily damaged than steel cylinders on

the outside and the threads where the cylinder valve screws in must be

inspected regularly for cracks and other problems. If water enters an aluminum

cylinder, the cylinder corrodes and forms aluminum oxide. Once aluminum

oxide has formed, it slows further corrosion to the cylinder.

Steel cylinders are more resistant to exterior damage. However, if water

enters a steel cylinder, the cylinder corrodes and forms rust that can quickly

ruin a steel cylinder. If you suspect that water has entered the cylinder, an

internal inspection should be made at a qualified facility.



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Scuba Cyl indersCylinders come in many d ifferent sizes.

n In the Metric system the

size of the cylinder is

expressed as the actual

volume of the cyl inder.

n In the United States the size

of the cylinder is expressed

as the volume of

compressed air the cyl inderwil l hold.

12-liter @ 200 bar

aluminum

10-liter @ 150 bar steel

80cu/ft @ 3000 psi

aluminum

65cu/ft @ 2250 psi steel

Scuba cylinders come in many different sizes. In the metric system, the size

of the cylinder is expressed as the volume the cylinder actually holds. In the

United States, the size of the cylinder is expressed as the volume of

compressed air the cylinder will hold.



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Scuba Cyl indersMarkings are placed on the shoulder of each cyl inder andprovide important information.

n The

Markings:

The markings include:

The serial numberof the cylinder, which is unique for each cylinder made by

a single manufacturer.

The name of the manufactureror their symbol.

Government-required marks to signify that the cylinder was manufactured

according to its standards.

The service pressure of the cylinder, which is the pressure to which the

cylinder can be filled (for example, 200 BAR or 3000 psi).

The material of which the cylinder is composed (for example, 3AL stands

for a particular aluminum alloy).

The hydrostatic testing date of the cylinder (for example, 8 97 signifies that

the cylinder was tested in August of 1997). In the United States, hydrostatic

testing must be performed every 5 years. In Japan, hydrostatic testing must be

performed every 3 years. In Australia, hydrostatic testing must be done every

year.

A + mark on steel tanks, authorizing a 10 percent pressure overfill beyond

the stamped service pressure. This mark will follow the current hydro date

stamped on the cylinder.



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Scuba Cyl indersAccessories.

n Tank Boot:

Allows rounded bottom cylinders to stand up

Protects the bottom of the cylinder

n Plastic Net:

Protects the exterior and paint of the cylinder

n Dual Manifold:

Hooks two cylinders together sharing a common valve

You must remove the boot on a cylinder periodically to properly rinse the

bottom of the cylinder.

The net protects the exterior of the cylinder and its paint.

You might also see divers with two cylinders hooked together with a

manifoldsharing a common valve.



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Cylinder ValvesEvery cylinder must have a valve to hold the air in. They actmuch lik e a water faucet . There are three types of valves:

n K Valve.

n J Valv e.

n DIN Valve.

The United States K valve is one valve you will see often when diving It is

designed like a post with an on/off knob. The first stage regulator yoke fits

over the post and the regulator is tightened against the post with a screw.

These valves are not usually used at pressures higher than 200 BAR (3000

psi). An O-ring or gasket found on the cylinder valve makes a seal between the

regulator and valve. If the O-ring is damaged or missing, the regulator will not

seal to the cylinder and air will escape.

A J valve looks like the K valve with a lever opposite the on/off knob.

This lever is known as a reserve mechanism. The mechanism was designed to

begin to restrict airflow at about 20 BAR (300 psi) to 33 BAR (500 psi) of

pressure in the cylinder. When the mechanism was manually opened, the

airflow was no longer restricted. The mechanism is rarely used because divers

now use submersible pressure gauges to monitor their air supply

The DIN valve system originated in Europe. The DIN valve has a large,

threaded opening and the regulator screws into the valve . This system is also

known as the captured O-ring system. While common in the rest of the world,

DIN valves are not commonly seen in the United States. The DIN valve is

stronger and capable of operating at pressures higher than 200 BAR (3000

psi).



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Cyl inder Valves:other considerationsEvery cylinder is equipped with a pressure relief disk orburst disk, which al low s excess pressure to vent safely.

n Maintenance.

n Visual I nspection.

n Hydrostatic Testing.

Proper care of your cylinder includes rinsing the outside with fresh water

after using the cylinder, having the cylinder visually inspected each year, and

having the cylinder hydrostatically tested as required by government

standards.

Scuba cylinders must be inspected internally and externally at least once per

year at a professional dive shop or a dive-equipment repair facility by a

certified cylinder inspector.

In the United States, hydrostatic testing is required every five years or

whenever the cylinder must be cleaned by tumbling. Hydrostatic testing tests

the cylinder for metal fatigue.



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Scuba Cyl inder StorageYou should store cylinders for any long term wit h somepressure in the cylinder.

n Steel Cylinders:

n Aluminum Cylinders:

n Never leave a cylinderstanding unattended:

In steel tanks, keeping some air in your cylinder ensures that water cannot

enter your cylinder and cause corrosion.

With aluminum tanks, this is not as much of a concern. Aluminum tanks can

be stored empty and with the valves open so that they will not be a hazard in afire. You should store cylinders upright in a cool, dry, and protected location

where they cannot be knocked over.

You should lay your cylinder down to prevent damage to it, the valve, or

injury to someone. When transporting a cylinder in a moving vehicle, place

the cylinder on its side and secure it to prevent damage to the cylinder, the

valve, or the vehicle.



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Review on Scuba Cyl indersWhat have you learned so far?

n What is the difference between a J valve and a

K valve?

n What two types of metal are used to make cylinders?

n How often do cylinders require a Visual inspection?

n How often do cylinders require a Hydrostatic test?







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RegulatorsThe scuba regulator is a mechanical device that delivers airto you on demand.

n Function:

n The Main Parts:

One function of the regulator is to reduce the high pressure of the air in the

cylinder to the ambient pressure, or the pressure surrounding your body, so

you can breathe it.

Regulators are composed of two main parts : the first stage and the secondstage. Regulators also commonly have other pieces of equipment attached to

them, including additional regulator second stages and gauges.



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Regulators:The First StageThe high pressure air from the cylinder is reduced toapproximately 9.6BAR (140psi) above ambient.

n Air from the first stage is

delivered to the second stage

through a low-pr essure hose.

n The first stage has a number of

outlets or ports to which hoses

and pieces of equipment are

attached.

n The low pressure ports allow the

fol lowing to be attached:

The first stage of most United States type regulators fits over the post of the

cylinder valve using a device combining theyoke andyoke screw. Some use a

DIN threaded fitting

The first stage must have at least one high-pressure port. This port bypassesthe mechanisms that reduce the pressure from the cylinder. Your submersible

pressure gauge is attached to this port so you can monitor your air supply.

The following hoses might be connected to low-pressure ports in addition to

your primary second stage hose:

A power-inflator hose for your buoyancy compensator.

An alternate second stage or octopus regulator.

A dry suit power-inflator hose, if used.



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Regulators:The Second StageThe second stage further reduces the air pressure fromapproximately 9.6 bar (140 psi) above ambient.

n The air you breathe is alw ays at the pressure

needed by your body, no matter how deep you

are under water.

n Some regulators offer higher performance.

The second stage of your regulator has a mouthpiece attached to it.

The second stage further reduces the air pressure from approximately 9.6

BAR (140 psi) above the surrounding pressure to whatever the ambient

pressure is. Therefore, the air you breathe is always at the pressure needed byyour body, no matter how deep you are under the water.

Some regulators offer higher performance than others and deliver a greater

volume of air at deeper depths regardless of flow restrictions. This is

important, because the deeper you go, the denser the air. If you plan to learn

to do deep, wreck, cave, or ice diving or do underwater hunting, you will want

a high-performance regulator.



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Regulators:Alternate Air SourcesIt is a standard practice for divers to be equipped w ith analternate air source that must be visible and easy to get to.

n Octopus Regulator.

n Combination

regulator and power-

inflator.

n Contingency Scuba.

It is standard practice that you and your buddy be equipped with alternate air

sources in case of emergency. An alternate second stage can be attached to

your primary regulator, or you can carry a source of air totally separate from

your scuba cylinder.

The most common alternate air source is an octopus regulator. The

octopus regulator is an additional second stage that allows you to share air

from your cylinder with another diver

Another type of alternate air source is a combination regulator and power-

inflator for your buoyancy compensator that fits on its power- inflator hose.

These units eliminate the extra hose for an octopus regulator and are easy to

locate in case of an emergency. The air donor typically uses this alternate air

source and gives their primary air source to the other diver.

Contingency scuba or true alternate air sources provide a totally independentregulator and air supply. The two main types of contingency scuba are: Apony

bottle, which is a small scuba cylinder with a separate regulator . Pony bottles

are commonly used by wreck divers and divers who dive deep. A smaller

cylinder with an integrated first and second stage mounted directly on the

cylinder

An alternate air source will not do you or your buddy any good if it

cannot be located immediately during an emergency.



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GaugesDivers must rely on gauges and instrum ents to tell themdepth, bottom time, direction and air supply

n Submersible pressure gauge (SPG).

n Depth gauge.

n The SPG and Depth may be combinedinto a console or used separately.

Divers must rely on gauges and instruments to tell them depth, bottom time,

direction, and air supply, just as a pilot relies on instrumentation to fly a plane.

The submersible pressure gauge (SPG) is a required piece of equipment for

scuba diving. The SPG displays the amount of air pressure remaining in yourscuba cylinder in the same way a fuel gauge shows how much gas you have

left in your cars gas tank

A depth gauge gives you a way to measure your depth when you are under

water.



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MaintenanceYour life-support system should be carefully maintained.

n Steps you can take:

n Steps that must be

performed by a

qualified technician:

Steps you can take:

At the end of each diving day, you should rinse your regulator with fresh water

to remove salt crystals or other impurities. Always be sure to let water run

through the mouthpiece and exhaust tees on the second stage. However, youshould never press thepurge button when running water through the

mouthpiece. This could cause water to enter the hose to the first stage and get

into the first stage of the regulator from there.

You should soak your regulator (if it does not have a DIN connector), alternate

air source, and gauges overnight in fresh water at the end of a dive trip, and

then rinse them thoroughly. Let the regulator dry completely and then store it

in a cool, dry place. Do not coil the hoses tightly or allow them to hang at an

angle with weight on them, which causes kinks at the hose ends. Hoses that

have been stressed can spring leaks and must be replaced.

The repair technicianwill take the first and second stages apart, clean all the

metal parts, and replace the O-rings and other nylon or silicone parts of the

regulator. The repair technician will also test and adjust the intermediate

pressure of your first stage during the service. During an annual service, the

repair technician will also inspect your submersible pressure gauge and high-

pressure hose, depth gauge, and compass for proper operation.



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Review on RegulatorsWhat have you learned so far?

n What is the most important criteria when selecting aregulator?

n What must be replaced before rinsing a regulator?

n What is an advantage to using a octopus regulator?

n What is the primary advantage to using contingencyscuba instead of an octopus regulator?

n Which Depth gauge is usable only at shallow depths?

n What measures the air pressure in your cylinder?







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Addit ional I nst rumentsSome addit ional diving instruments that you might w ant toconsider using include:

n Timing devices.

n Dive computer withat least thefol lowing:

n Back-upInstrumentation.

n Maintenance.

Timing Devices: Watches used for diving must be designed to withstand pressure.

They should be rated for depths of at least 100 meters (300 feet). Your watch should

also have a way to measure elapsed time with one of the following: A rotating bezel

around the dial of the watch. A stopwatch feature. The dive timer automatically

records the elapsed time of your dive without action on your part.

At a minimum, a typical dive computer records or displays the following

information: Maximum depth, Current depth, Actual dive time, Remaining allowable

dive time. Between dives, the computer can display information from your previous

dives as well as the amount of time that you have been out of the water. The

computer can also help you plan your next dive by telling you how long you can stay

at different depths.

If you use a dive computer, you should back it up with a second computer or a

watch and a depth gauge. If you use an air-integrated computer, you should back it up

with a submersible pressure gauge, depth gauge, and watch.

Rinse your instruments in clean, fresh water at the end of each diving day and have

your instruments inspected and serviced once per year by a qualified repair technician.



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Review on I nst rumentsWhat have you learned so far?

n What calculates your remaining allowable bottom

time while diving?

n What two things must a dive watch do?

n What are two proper maintenance items for your

instruments?







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Buoyancy Cont rol DevicesBuoyancy control is one of the most important skills youw ill learn as a diver.

n A buoyancy control device (BCD) or

buoyancy compensator (BC).

n Features:

n Types:

A buoyancy control device (BCD), or buoyancy compensator (BC), enables you

to control whether you float on the surface of the water, hover in the water, or sink

to the bottom. You control this by adding air to or venting air from your BC

Features: BCs must be equipped with an overpressure relief valve to preventdamage to the BC from too much internal air pressure. The BC must also have an

inflator/deflator hose that is at least 2 centimeters (3/4 inch) in diameter. At the

end of the inflator/deflator hose is apower-inflator mechanism and a deflator/oral

inflator valve. All BCs are also equipped with a mouthpiece at the end of the

inflator/deflator hose that enables you to inflate the BC by blowing air into it

Types: Back-flotation systems are designed so that the entire bladder of the BC is

behind you. This leaves your chest and waist uncluttered. Back-flotation systems

are popular for underwater photography for this reason.

Jacket-style BCs are the most popular buoyancy control devices. These BCs aredesigned so that the bladder wraps from your back around to your waist. These

BCs are comfortable to wear, provide good trim under water, and float you upright

on the surface when your BC is inflated.

The older horse collar design encircles your neck. You can use a horse collar for

both skin and scuba diving.



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BCD: Integrated W eight SystemsSome BCs enable you to integrate or add your w eightsdirectly to the BC.

n The advantages of weight integrated:

No weight belt.

Weights cannot slide around.

Weight is not supported solely by your back.

n Disadvantage to the weight integrated system:

Once assembled, it can be heavy and awkward to

handle.

Hard to tell how much weight is on the BC just by

looking at it.

Some integrated-weight systems use pockets that you load with weights and

then secure in your BC with Velcro. In an emergency, you pull the entire

pocket out of the BC and drop it.

A potential major hazard is that it is impossible for a dive supervisor to tell at aglance approximately how much weight you are wearing (for example,

whether you are obviously overweighted).



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Review on BCDsWhat have you learned so far?

n What are the three main types of BCs?

n What are two essential features found on all BCs?

n Why should you rinse the inside of your BC?







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Weight s and Weight belt sYou w ear lead weights w hen you are diving to offset thebuoyancy of your body, wetsuit and other equipment.

n Types of Weights.

n Weight belts, harnesses andw eighting systems.

n Quick release of weights.

Weights are available in many configurations and as you gain diving

experience, you will find the configuration that fits you best.

Types: Most commonly, you will find lead molded into cylinders or blocks

with slits to enable a weight belt to be threaded through the weight. The blockof lead can be uncoated or coated with a plastic covering. Some of the larger

blocks of lead are curved to fit the hip and are known as hip weights.

Weighting Systems : The simplest and most common weight belt is a 5.0

centimeter (2- inch) wide nylon web belt with a metal or plastic buckle.

Weight keepers are used on this type of weight belt to keep the weights from

shifting on the belt. A weight harness, usually used with dry suits, uses a belt

and shoulder harness system to support the weights on your shoulders rather

than around your waist.

Some weight belts are composed of a series of pockets attached to a nylon web

belt. These pockets will hold either solid weights or soft weights.

No matter what type of weight system you choose, you must have a means of

ditching the weights with one hand. This type of system is known as a quick

release



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Unit2-D

ivingEquipment

Review on Weight s and BeltsWhat have you learned so far?

n The most important feature of the weight belt?

n What does a compensating weight belt do?

n Why might divers prefer soft weights over

molded lead weights?







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Diving Suit sDivers mu st wear a thermal-protection diving suit in all butthe warmest waters.

n The amount of insulation depends on:

Water temperature.

Activity level during the dive.

Your build, body fat, etc.

n Three types:

Dive Skins.

Wetsuits.

Dry Suits.

The amount of insulation:

It is essential to wear the right thermal protection for the conditions where you dive.

When you grow cold under water, you lose your ability to perform at your best



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Diving Suit sDifferent ranges of temperature feel comfortable todifferent divers.

n Dive skins:

Tropical waters.

Protective covering to avoid injuries and sunburn.

Most common types, Lyrca and Polartec.

n Wetsuits, made from neoprene rubber:

Must fit precisely and snugly.

Water that is trapped in the suit keeps you warm.

Available from 2 to 7mm in thickness and styles:

Shorty.

Farmer john. Step-in.

One piece.

Dive skins are thin, one-piece suits designed to protect your skin from cuts,

scrapes, and stings that can occur when you dive in tropical waters

Wetsuits are made from foam neoprene, which is a synthetic rubber filled with

thousands of tiny gas bubbles. Neoprene provides good insulation in manydiving situations. Wetsuits are the most widely used thermal protection for

divers because of their simplicity and relatively low initial cost.

Wetsuits are available in many thicknesses from 2 millimeters (mm) to 7 mm

and Shorty wetsuits (wetsuits with short sleeves and thigh-length legs) and 2

mm or 3 mm full-body suits are popular for wear in tropical temperature

water. For colder water diving, some divers prefer to wear a bib overall set of

pants known as afarmer john and a step-injacket combination. They also

wear a hood, booties, and gloves.in many different styles.



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Diving Suit sDifferent ranges of temperature feel comfortable todifferent divers.

n Drysuits:

Designed to keep you dry.

Used in colder water.

More expensive than wetsuits.

Dry suits are preferred for colder water. Dry suits are much more expensive

than wetsuits, but are well worth the cost for the increased comfort in many

diving situations. A dry suit is designed to keep you dry. The suit keeps you

dry by using a combination of wrist seals, a neck seal, and a waterproof zipper



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Diving Suit s:Wetsuit optionsIf your measurements are different from standard sizesyou might consider a custom made w etsuit.

n Options for wetsuits can include:

Zippers at the wrist and ankles.

Knee pads.

Spine pad.

Pockets inside the wetsuit.

Sheaths to hold a knife.

Attached hood.

Pockets on the outside.

Options for wetsuits can include: Zippers at the wrists and ankles to make the

suit easier to put on. However, water can enter and leave the suit through the

zippers, chilling you. Knee pads to protect your knees and the suit from sharp

rocks. A spine pad to cushion the cylinder and keep the spine warmer. Pockets

inside the wetsuit to hold keys. Sheaths built into the leg to hold a dive knife.

Attached hood for extra warmth.



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Diving Suit s:Choosing the right suitThe correct suit for the conditions is one of the key s toenjoying a dive.

n Use the fol lowing guidelines when deciding whattype of diving suit to wear:

n 27 C (80 F) and warmer water

Dive skin

n 23 C to 30 C (75 F to 85 F) waters

2 to 3mm ful l wetsuit or shorty


5 to 7mm ful l wetsuit


Full dry suitn 2 C (35 F) and colder waters

Special training and equipment are needed

The correct suit for you might not be the correct suit for your buddy because

your reaction to cold might be quite different. Also, depending on the area of

the world in which you live, your resistance to cold might be less. For

example, if you live in a desert climate, you might have to wear more

insulation because your body is accustomed to high temperatures. If you live

in a cold climate, you might be wearing less insulation in the water because

your body is accustomed to colder temperatures.



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Diving Suit s:MaintenanceYou should rinse your diving suit w ith fresh w ater afterevery diving day.

n Maintenance includes:

Rinse dive skins and wetsuits inside and out.

Commercial products are available to help clean your

suits completely before storage.

Store your suits on wide hangers designed especially for

them.

Maintenance

You should rinse a diving suit with fresh water after every diving day. Rinse

dive skins and wetsuits inside and out. There are commercial products you

can use at the end of a dive trip to clean your dive suits completely beforestorage. You should store your wetsuits on wide hangers designed especially

for wetsuits, or unfolded, lying flat. If you get a hole in your wetsuit, you can

repair it with wetsuit cement and neoprene patch material.



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Unit2-D

ivingEquipment

Review on Diving Suit sWhat have you learned so far?

n Which suit is should be used for warm, tropical

diving?

n Which suit is made from neoprene rubber?

n Which suit uses an under garment?

n Which suit requires specialized training?







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Accessory EquipmentSome other useful accessories are:

n Underwater slate.

n Goodie bag.

n Underwater l ight.

n Marker buoy and line.

n Spare parts kit.

n Checklist.

An underwater slate so you can record data and communicate with your

buddy.

A goodie bag to hold game, specimens, artifacts, trash, and other treasures.

An underwater light, which is necessary for night diving, but is also good to

have during the day to bring out colors and to peer into holes and crevices.

A marker buoy to mark the location of a dropped item or a specific area.

A spare parts kit that includes the items that can save a dive. The items can

include a mask strap, a snorkel keeper, a fin strap, assorted O-rings, and a

regulator mouthpiece with attachment strip.

A checklist is a great way to remember all of the gear you need for diving aswell as personal items. See Appendix C for samples of checklists.



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Unit2-D

ivingEquipment

Review on Accessor iesWhat have you learned so far?

n What is the most likely use for a knife

underwater?

n What must you do when you fly a dive flag?

n What are two reasons for logging your dives in

a logbook?

n Name two additional accessories that are

useful when diving?







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Unit2-D

ivingEquipment

Diving Equipm ent : End of Unit 2

n Basic equipment.

n Scuba cylinders.

n Scuba regulators

n Diving instruments.

n Buoyancy compensators.

n Weighting systems.

n Diving suits.

nAccessory equipment.

Transition Statement: Scuba diving depends on our ability to adapt to analien environment with the help of specialized equipment. This unit hashelped you understand how to use and care for scuba equipment.

Review of Main Points: See this presentation slide.

Emphasize Key Points:

Ask Students for Questions:



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Unit2-D

ivingEquipment

n List the basic equipment you need to go skin diving.

n Describe scuba cylinders, including types and sizes, valves,maintenance, and inspections.

n Describe regulators and the equipment usually attached to theregulator.

n List the different types of diving instruments.

n Describe the types of buoyancy control devices and how toselect one that meets your needs.

n Describe the use of weighting systems.

n List the different types of diving suits used for warmth and

protection and describe how to choose the right suit for yourdiving conditions.

n List the accessory equipment that makes diving more enjoyable.

St udent Perform ance:By the end of the lesson students will be able to:

Restate the students performance statements as questions:

Assignment:

Instruct the students to read chapter 3 in preparation for the next lesson.

unit 2- diving equipment

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