Samui Dive Supply

SCUBA DIVING EQUIPMENT FIRST STAGE REGULATORS

noreply@blogger.com (Samui Dive Supply) — Sun, 18 Jan 2009 05:18:00 +0000

SCUBA DIVING EQUIPMENT FIRST STAGE REGULATORS

Back again with some information regarding the first stage scuba diving regulator.

There are two basic first stage regulator designs the piston or diaphragm and then two versions of each design in the balanced or unbalanced.

With the Piston and Diaphragm first stage regulators the differences are:

In a diaphragm first stage, water pressure is transmitted to the valve through a flexible diaphragm. The valve itself is sealed against water intrusion, and the spring chamber can be easily sealed as well. Because water cannot enter the first-stage housing, internal corrosion is minimized. On the other hand, diaphragm first stages have more moving parts and may not lend themselves as well to swivel fittings for low-pressure hoses, because intermediate pressure comes out in the middle of the housing.

In a piston design, water pressure acts directly on the valve, making it simpler, with fewer moving parts. They are easy to adapt to swivel fittings, making low-pressure hose placement more convenient. But because water enters the spring and piston chamber, pistons are more sensitive to corrosion, especially if the owner neglects regular maintenance.

Balanced vs. Unbalanced

Both piston and diaphragm first stages come in balanced and unbalanced versions. A valve is balanced by extending the shaft beyond the pressure chamber so air pushes on both ends equally. A balanced first stage retains ease of breathing all the way down to the last few pounds of tank pressure, because intermediate pressure remains constant. These units are more complex and generally more expensive.

Until a few years ago, unbalanced first stages were severely affected by low tank pressures and would begin to breathe harder below about 700 psi. The reason was a 30- to 40-psi drop in intermediate pressure from full to near-empty tanks. But current models are less sensitive to supply pressure, with a pressure drop of only 20 to 30 psi. Therefore, the performance gap between balanced and unbalanced first stages has tightened. Unbalanced first stages are more economical, have fewer moving parts and are easier to service. But they will usually have fewer ports and lack the convenience of swivel mounting.

A simple description of the regulator first stage would be as follows;

The system operates like this:

1. You inhale, thereby lowering the pressure in the intermediate-pressure chamber to below the ambient water pressure.

2. The water pressure pushes inward, opening the valve or piston.

3. The open valve connects the high-pressure chamber with the intermediate pressure chamber.

4. Air flows from the high-pressure chamber into the intermediate-pressure chamber, thereby increasing the pressure in the intermediate-pressure chamber.

5. When the pressure in the intermediate-pressure chamber equals the ambient water pressure, the valve or piston closes.

6. The process repeats when you inhale again.

Look out for the next more detailed posts on Open Circuit SCUBA equipment Second Stages.

Please feel free to comment on any posts in this blog.

To find out more about SCUBA equipment available from Samui Dive Supply please contact us for more information.

SELF CONTAINED UNDERWATER BREATHING APPARATUS (SCUBA) (PART 2)

noreply@blogger.com (Samui Dive Supply) — Sun, 02 Nov 2008 05:12:00 +0000

Self Contained Underwater Breathing Apparatus (SCUBA) (Part 2)

So if you have read the post SELF CONTAINED UNDERWATER BREATHING APPARATUS (SCUBA) (PART 1) I am sure you will now be aware that it is all a matter of bubbles. We will concentrate on Open Circuit SCUBA, the one which vents bubbles every time you breathe out, and its fundamental components.

There are four components to Open Circuit SCUBA equipment:

High Pressure Breathing Gas Cylinder

Your breathing gas cylinder will normally be manufacture of either Steel or Aluminum. It will have an outlet valve that opens or closes the cylinder and permits the second component of SCUBA, the regulator, to be attached to the cylinder. The working pressure of the cylinder can vary from 200 bar to 300 bar and vary in size from 8 litre cylinders, suitable for junior divers up to 15 litre cylinders, great for air hogs.

The Regulator

The SCUBA regulator is a two stage pressure regulator which provides you with your breathing gas on demand from you cylinder when you inhale. The first stage regulator will reduce the gas pressure from your cylinder to an intermediate pressure (IP), typically 9 – 10 bar, which in turn will then be reduced by the second stage demand regulator to the ambient pressure for breathing.

Your first stage regulator would also have fitted an alternative air source regulator (AAS) or octopus for sharing breathing gas with your dive buddy in an emergency situation, an gas pressure gauge (SPG) that indicates your current cylinder gas pressure and a low pressure inflator (LPI) hose which supplies gas to your BCD at the IP to assist with you buoyancy control.

Buoyancy Control Device (BCD)

The majority of recreational divers use an inflatable jacket style BCD to control their buoyancy. Through the use of the LPI connected to your cylinder via the LPI hose gas can be added to or released from your BCD to assist you in attaining either neutral buoyancy whilst under the water or make you positively buoyant for resting at the surface or surface swimming.

Your BCD will also include a backpack to which your cylinder will be attached using bands thus holding you SCUBA system together in one integral unit. When we cover the BCD in more detail in a later post we can discuss the different styles.

Weight Systems

When diving, you use a weight system to just offset any buoyancy. It may be on a weight belt around your waist, a harness on integrated into your BCD.

Look out for the next more detailed posts on Open Circuit SCUBA equipment.

Please feel free to comment on any posts in this blog.

To find out more about SCUBA equipment available from Samui Dive Supply please contact us for more information.

SELF CONTAINED UNDERWATER BREATHING APPARATUS (SCUBA) (PART 1)

noreply@blogger.com (Samui Dive Supply) — Sun, 26 Oct 2008 06:33:00 +0000

Self Contained Underwater Breathing Apparatus (SCUBA) (Part 1)

A month or so ago, doesn’t time fly when you’re having fun, we said we will introduce SCUBA equipment to you, attempt to explain what it is and what it does for you.

As an introduction there are three basic types of SCUBA equipment:

Open Circuit

When you breath in you use a two stage regulator that provides gas at the ambient pressure from a tank of compressed gas usually at 200 bar. When you breath out through your regulator second stage the exhaled air vents into the water as bubbles. Your SCUBA equipment would also consist of a Buoyancy Control Device (BCD) and weight system. This is the system we will focus on in more detail in the next post. An example of an Open Circuit Regulator would be the Scubapro Mk25 1st Stage witha S600 2nd Stage.

Semi-Closed Rebreathers (SCRs)

When you breathe in, you breathe from a counter lung in your SCR. When you breathe out your exhaled air passes through a scrubber that removes the excess carbon dioxide in the exhaled air. This air then passes into the counter lung where it mixes with oxygen that is flowing at a continuous set flow rate to produce your breathing gas. Any excess gas in the counter lung is vented off as a small stream of bubbles. An example of a SCR would be the Drager Dolphin.

Closed Circuit Rebreathers (CCR’s)

When you breathe in, you breathe from a counter lung in your CCR. When you breathe out your exhaled air passes through a system that removes the waste carbon dioxide in the exhaled air and replaces consumed oxygen then it returns to the counter lung. There are no bubbles. An Example of a CCR would be the Pelagian from RebreatherLab.

Look out for the next post on Open Circuit SCUBA equipment.

Please feel free to comment on any posts in this blog.

To find out more about SCUBA equipment available from Samui Dive Supply please contact us for more information.

BASIC EQUIPMENT FOR SCUBA DIVING AND SNORKELING (Part 4)

noreply@blogger.com (Samui Dive Supply) — Sat, 30 Aug 2008 04:38:00 +0000

Basic Equipment for SCUBA Diving and Snorkeling (Part 4)

This week we have the second of two Blog posts covering the topic of the highly essential piece of diving/snorkeling equipment FINS.

Fins

To recap the basic function of a fin is to propel you the diver/snorkeler through the water with as little effort as possible for the most propulsion, to this end there are a multitude of designs now available on the market to suit everybody’s needs.

A fin consists of a foot pocket, either full foot “slipper fins” or open heel, and a blade which can be of many different designs.

In this Blog post we will cover the Open Heel adjustable design fins which are used predominantly by seasoned divers, dive professionals and in colder waters.

Open Heel Adjustable Fins

These fins are generally larger than full foot fins and provide more power which greatly assists the diver when wearing a full set of SCUBA diving equipment. We will introduce SCUBA equipment in the next Blog post, they have an Open Heel, hence the name, foot pocket with an adjustable strap to hold the foot in the foot pocket. The foot pockets come in a variety of sizes from extra small to extra large so they can encompass all foot sizes. The use of neoprene boots is also required.

The fin straps are generally made of rubber and are fixed to the fins using adjustable buckles some fin buckles also have a quick release mechanism to allow the diver to easily remove the fin strap and fin, especially useful when waiting to climb up the ladder of a boat. There is also the option to use spring heel straps such as the Saekodive Spring Strap with buckle. In place of the rubber strap a high powered spring is used to hold the foot in the foot pocket.

The blades are made from either rubber such as the Scubapro Jet Fin Classic or a mixture of rubber and techno polymers which encompasses the benefits on both materials.

The blades can incorporate channels to ease the flow of water across the fin but at the same time maximizing the thrust a good example of these would be the Seac Sub Propulsion fins and some fins have a split fin design which provides the diver/snorkeler with a propeller thrust effect, see diagram, such as the Scubapro Twin Jet fin or Max Twin Jet Fin.

You would normally find ribs down the edges of the blades, these tend to aid the flow of water down the length of the blade enhancing thrust and preventing the blade from twisting under stress.

To find out more about fins available form Dive Supply please contact us for more information.

Don’t miss the next Blog post an introduction to SCUBA by adding us to your RSS feed.

Own fins already? Why not take part in our poll to see which are the most popular brand fins used by our Blog readers.

BASIC EQUIPMENT FOR SCUBA DIVING AND SNORKELING (Part 3)

noreply@blogger.com (Samui Dive Supply) — Sun, 10 Aug 2008 09:35:00 +0000

Basic Equipment for SCUBA Diving and Snorkeling (Part 3)

This week we start the first of two Blog posts covering the topic of the highly essential piece of diving/snorkeling equipment FINS.

Fins

The basic function of a fin is to propel you the diver/snorkeler through the water with as little effort as possible for the most propulsion, to this end there are a multitude of designs now available on the market to suit everybody’s needs.

A fin consists of a foot pocket, either full foot “slipper fins” or open heel, and a blade which can be of many different designs.

In this Blog post we will cover the full foot design fin which is used predominantly in Dive Shops in tropical locations as their rental fin or by snorkelers.

Full Foot Fins

So called because the whole foot of the diver/snorkeler is enclosed in a foot pocket made of rubber or neoprene these fins are usually used in warmer waters by divers and snorkelers. The comfort of these fins usually depends on the quality of the rubber or neoprene used on the foot pocket. Cheaper fins tend to use a more rigid rubber that can, if the fin does not fit correctly, rub and cause blisters on the feet or if beach diving/snorkeling it is wise to ensure you have no sand on your feet before fitting the fins to avoid chaffing. More expensive models tend to use higher quality more comfortable foot pockets that tend to eliminate the problem of blisters. For sizing you would normally choose the size that corresponds to your shoe size. Always try before you buy as the foot pocket will usually cover two shoe sizes and the correct fit is essential for your enjoyment.

The blades are made from either rubber, which can be rather heavy for a full foot fin, techno polymer which is light or a mixture of rubber and techno polymers which encompasses the benefits on both materials.

The blades can incorporate channels to ease the flow of water across the fin but at the same time maximizing the thrust, have a split fin design which provides the diver/snorkeler with a propeller thrust effect or a hinge/energy storage system which provides most thrust on one stroke and effectively storing energy on the opposite stroke.

You would normally find ribs down the edges of the blades, these tend to aid the flow of water down the length of the blade enhancing thrust and preventing the blade from twisting under stress.

To find out more about fins available please contact us for more information.

Don’t miss the next Blog post on Full Foot Fins by adding us to your RSS feed.

Own fins already? Why not take part in our poll to see which are the most popular brand fins used by our Blog readers.

BASIC EQUIPMENT FOR SCUBA DIVING AND SNORKELING (Part 2)

noreply@blogger.com (Samui Dive Supply) — Mon, 04 Aug 2008 04:10:00 +0000

Basic Equipment for SCUBA Diving and Snorkeling (Part 2)

Following on from last weeks post regarding the basic equipment required for SCUBA diving and Snorkeling this week we will cover the most basic piece of equipment the humble snorkel.

Snorkels

Considered by some as a mandatory piece of diving equipment, by others a recommended piece of equipment and by others a nuisance, the snorkel does have its uses, even if it is only to ward of aggresive Titan Trigger fish!

The basic function of a snorkel is to permit you to breathe at the surface without lifting you head out of the water. When snorkeling this provides you with a great view of the undersea world from the surface allowing you to spot something you want to take a closer look at and without loosing sight, make a surface dive and take a closer look, all in one easy movement. For divers the snorkel allows you to fin face down in the water at the surface to your descent point, providing a lower profile than swimming on your back hence being less tiring. If you surface some distance from your exit point the same can be said. This is even more important in choppy water when fining on your back may not be possible.

The key features of a snorkel in today’s world would include a large bore tube designed with smooth bends, a comfortable mouthpiece, self draining tube and an easy to use snorkel holder.

The tube is generally made from plastic, look for flexible plastic as it makes it more resistant to impact, with a silicone or rubber mouthpiece, silicone tends to be the material of choice unless you like the taste of rubber.

Snorkel Styles

Snorkels should be between 35 and 45 cm in length depending on the size of the head of the diver/snorkeller this will ensure that the snorkel is long enough to protrude from the water surface whilst the diver/snorkeller has their face immersed and at the same time is not too long as to extend the dead air space and provide the minimum of breathing resistance, hence the bore of the snorkel should be between 19 and 25 mm so that it is possible to clear the snorkel easily.

Some snorkels have a flexible part attached to the bottom for the tube an example of this would be the Scubapro Escape snorkel, this allows a SCUBA diver to let the mouthpiece hang free and away from their face when using their regulator, for the snorkeller it allows a degree of lateral movement without disturbing the mask seal. When choosing a flexible bottom portion try to find one with a smooth internal face to reduce internal turbulence when breathing.

Most snorkels now incorporate a one way valve at the base or below the mouthpiece. Exhale sharply and any water will be expelled through the valve as well as through the top of the snorkel to permit easy breathing. In addition some snorkels include devices at the top to minimize water from spray and choppy seas entering the tube the Scubapro Trinidad Snorkel would be a model with these attributes.

Your snorkel will attach to your mask strap using a snorkel holder. These range from a simple figure of 8 PVC strap to hard plastic clips or clips that have clever mechanisms to easily detach the mask from the snorkel for storage. For the diver who is not fond of wearing his snorkel attached to his mask underwater there a variety of foldaway snorkels that can easily fit in your pocket.

To find out more about the snorkels available today please contact us for more information.

Next Post: Fins

BASIC EQUIPMENT FOR SCUBA DIVING AND SNORKELING

noreply@blogger.com (Samui Dive Supply) — Sun, 27 Jul 2008 05:13:00 +0000

Basic Equipment for Scuba Diving and Snorkeling

The items generally considered as basic equipment are your Mask, Fins and Snorkel.

These three items of scuba/snorkeling diving equipment are used to allow your eyes to see your legs to propel yourself and your body to breath.

The mask provides air in front of your eyes so that they can focus thus enabling you so see the underwater environment you have come to view whether diving or snorkeling. The snorkel provides a means for you to breathe at the surface whilst your head is immersed in the water, when snorkeling this allows you to view items of interest from the surface before descending to take a closer look and whilst SCUBA diving it helps you conserve energy and air whilst swimming on the surface. Fins will allow you to move through the water quicker but with less effort when snorkeling thus enabling you to see more of the snorkel site when diving they allow you to overcome the added drag that results from the SCUBA system on your back.

Masks

Our eyes are not designed to focus underwater so we use a mask to provide airspace in front of your eyes to enable them to focus. If you did not have a mask for sure you would not go diving or snorkeling but if all you had was a mask you could still view the wonders of the underwater world in shallow water.

Although masks have changed in many was since their inception they basically consist of the same elements these being a clear face plate, flexible sealing skirt and a strap.

The faceplate is made from tempered glass, this type of glass is used because in the unlikely event that the glass should break it clings together thus limiting the hazard of sharp splinters. The glass can be in one piece for your eyes, single lens or two pieces, one for each eye, double lens. The lens is mounted in a frame usually made from a plastic or composite material and comes in many colours and shapes.

The flexible sealing skirt is usually made from clear or black silicone, although divers and snorkelers tend to prefer clear silicone skirts as the allow more light to enter the eyes there are a few divers such as underwater photographers and technical divers who favor black silicone so that they can reduce the amount of stray light entering there mask and distracting them form the tasks they have at hand. This skirt would also encompass a flexible nose pocket to enable the diver/snorkeler to equalize the pressure in their mask and ears.

The Strap is quite simple single or double band made from silicone, rubber or neoprene. They are adjustable in length for the users comfort.

Mask Styles

Masks are now available in many different styles from large oval single plates, rarely seen now, to high tech masks with integrated head up displays.

Some masks try to give the best field of vision possible either horizontally like the Scubapro Crystal View complete with integrated seamless side windows or vertically such as the Seac Sub Italica mask offering an almost unlimited field of vision with twin inclined lenses.

Some divers prefer low profile masks as they are easy to equalize and clear. Also being low profile the faceplate is closer to the eyes thus providing a good field of vision although not quite as good as the special features listed above provide. Examples of these masks would be the Seac Sub extreme mask, Seac Sub Libera Mask and Saekodive Runner Mask.

Frameless masks are now becoming quite popular with many options available on the market the Scubapro Trinidad being on such model, not having a frame reduces the weight of the mask leads to a low volume and good field of vision.

If you would like to know more about masks contact us we have a wide selection including those featured in this post available.

Next post: Snorkels

Welcome to Samui Dive Supply

noreply@blogger.com (Samui Dive Supply) — Mon, 21 Jul 2008 05:06:00 +0000

Samui Dive Supply is the leading retailer and wholesale supplier of quality diving, snorkeling and water sports equipment on Koh Samui. In this blog we will aim to provide you with information regarding dive equipment currently available in Koh Samui form new products to old favourites and some general information about dive equipment.

Supported by the largest warehouse facility for scuba diving equipment in Thailand we can offer an unsurpassed level of service to any dive centre, snorkel tour operator, hotel/resort or retail outlet on Koh Samui and Koh Phangan.

If you are in the area please feel free to visit our showroom on the Samui ring road in Chaweng located between the PTT gas station and the Bangkok Samui Hospital.

Stocking leading brands such as Scubapro, Suunto, Seac Sub, Bauer, Ocean Management Systems and Saekodive you can be sure to find what you want when visiting Samui Dive Supply.

If we do not currently hold stock of the dive equipment you want at the Samui Dive Supply showroom we can order most items of scuba diving or snorkeling equipment from our warehouse facility with a delivery time of between two and seven days.

We are open everyday from 9:00 am to 6:00 pm ready to serve you with our expert product knowledge.