Drysuits are Sealed Watertight for Diving in Frigid Water
If you dive in waters below 50 or 60 degrees Fahrenheit, you probably will need a drysuit. Just ask the urchin divers and mussel harvesters who scuba dive daily in the frigid North Atlantic waters.

Drysuits keep the diver dry and warm with a water-tight seal. Frigid waters cannot seep into the suit. Undergarments -- thermal underwear and wool socks -- are worn under the drysuit for an added layer of protection. Wrist and neck seals often are coated with silicone spray. Gloves and a hood also are worn.

Drysuits are inflated when divers enter the water. The air helps with buoyancy and keeps divers warm. Drysuits are deflated on ascent.

Scuba Regulators: Try Before You Buy
LeisurePro Tip: When you're learning to scuba dive, you probably will train with rented equipment. It may be wise to vary the equipment you rent, including the type of scuba regulators you use, so when you are ready to purchase your own scuba regulator you can buy with confidence.
The two stage single hose regulator is the most commonly used regulator in scuba diving. It is light and allows a diver to "breathe easy." As the name implies, a scuba diver only has to check the fit of one hose before his dive.
The double hose regulator works well in icy water. It also is great for underwater photographers, as exhalation bubbles are released behind the head, so as not to block your view. A comfortable mouthpiece that fits your regulator is essential to a great dive experience. No matter which type of scuba regulator you choose, try both plastic and metal mouthpieces, determine your preference, and then get it custom fitted to your mouth.
Choose a Scuba Watch That is Rugged and Reliable
Scuba computers go by a lot of names: dive computers, dive watches, decompression meters, scuba watches. But they all have the same primary function: They measure the time and depth of dives to calculate a safe ascent.
Here are some features to look for in a dive computer watch:

• Dive watches need to be made of titanium or another noncorrosive material.
• The buttons must be big enough to be handled by a diver wearing gloves.
• The watch needs to be rugged and able to resist the wear and tear of an underwater dive. The
• watch face should be scratch-resistant.
• Make sure the scuba watch you buy can go to the depths you dive.
• The dial, settings and numbers need to be illuminated and easily seen from a foot away underwater.
• The wrist band should have a strong clasp that is not prone to breaking.

Scuba Students Need to Use Standard Equipment in Class
If you are new to scuba diving or are a diving student, you will need a basic understanding of equipment. From the mask to fins, each piece of diving equipment has an essential function and purpose.
Scuba courses have classroom-based work. But a lot of the instruction takes place in the water, where you will learn to dive under the supervision of the instructor. Don't expect to make a big investment in equipment at the start. But you will need to buy a starter package consisting of mask, fins, snorkel, weight, weight belt and boots.
While it is not necessary to get the most expensive set, you want equipment that will not crack or leak from frequent use and exposure to saltwater. The bottom line with diving equipment is to go with brands that have a track record for quality.
Your diving instructor will explain the purpose of each piece of scuba equipment. You should not be required to buy anything beyond mask, fins, snorkel, weight, weight belt and boots. But you will need to rent dive equipment to participate in diving school. Usually certifying instructors are affiliated with dive shops and have rental equipment on hand.
Here's a rundown of standard scuba equipment that will get you started:

• Mask, fins, snorkel.
• Buoyancy compensator, also known as a BC or BCD. This inflatable jacket adjusts your buoyancy in the water.
• Regulator: This is the bit or mouthpiece from which you breathe. It is connected to air cylinder.
• Weight belt: The belt holds you down in the water. Weight belts sometimes are integrated with the buoyancy compensator.
• Air cylinder: The steel or aluminum cylinder holds compressed air that you use underwater.
• Octopus: This is your alternate air source
• Instrument: Gauge that can display your air supply and depth.

Choose the Best Dive Bags For Your Gear
You've made an investment in your scuba gear, so make sure you take care of it. Especially after a dive, it's easy just to scatter your stuff. Consider buying a few different dives bags for holding and transporting your scuba gear.
Here is a checklist of dive bags that any serious recreational or sport diver will need:

• Mesh bags: These are the bags for carrying your scuba gear to the dive boat or dive site. The netting on these bags allows water to drain easily from them.The duffel bag style is standard, though the backpack style can be convenient because your hands are free. There also are tank bags and bags for holding your snorkel, mask and fins. Shop for mesh bags that have a rubber coating, which makes them more durable. It's never a bad idea to have extra mesh bags on hand.
• Travel bags: These heavy-duty cargo bags are for trips, and most come with wheels. You can get a duffel-bag, cargo or backpack style travel bag. Look for travel bags with collapsible handles and interior dividers. Think twice before placing any kind of scuba sticker or insignia on your travel bag. While you may think the sticker will cause cargo handlers to transfer the bags with care, you are making the travel bags vulnerable to theft.

Scuba Tank Considerations
LeisurePro Tip: A scuba tank is a cylinder that holds compressed breathing air for the scuba diver. There are two types of scuba tanks: the aluminum tank and the steel tank. When choosing between the two scuba tanks, it is important to consider the following:
A steel scuba diving tank has excellent buoyancy characteristics and comes in a variety of sizes. It generally weighs less than an aluminum tank. A properly maintained steel diving tank can last the life of the diver. The steel scuba tank is significantly more costly than the aluminum tank, but because it can last up to 40 years, it is very cost-efficient.
The aluminum scuba diving tank requires more maintenance than the steel scuba tank. It has poor buoyancy properties, so it must be counterweighted to keep from floating at the end of a dive. The average lifespan of an aluminum tank is 15 years, but it is significantly less expensive than a steel tank.

Prepare During the Day for Night Dives
Make your night dive enjoyable by doing advance preparation. The prep work ensures your dive party's safety and allows you to focus on the adventure itself. The better you plan the more prepared you are for unexpected problems, whether it is foul weather or a piece of equipment that fails.

• Pack your primary scuba light, a backup light and marker light, which should illuminate your ascent line. Bring fresh batteries.
• Organize your diving equipment during daylight hours. Make sure all safety equipment is on board the dive boat.
• Check weather and current conditions ahead of time. Make sure your dive buddy is outfitted and ready to go.
• When diving, don't shine your strobe in your buddy's face. It will temporarily blind and disorient the diver.
• Don't switch your dive light off and on frequently. Equipment failure usually happens with the switch.
• Try to dim your light by covering it with your hands, so you do not over brighten the underwater area you are viewing.
• Learn light signals that divers use at night. Waving your light up and down means "Help!" Making a big circle with your light signals "OK."
• If you surface far from the boat, shine the light on it to get attention. Then shine the scuba light on your head, so the dive boat can get to you. If you keep the light on the boat, no one will be able to see and find you.

Choose a Mask That Fits Well and Doesn't Leak
What makes one scuba mask better than another? Divers want to see well in the water. But there are several features to consider:

• The dive mask should fit well. Press it against your face and breathe in through your nose. It should create a tight vacuum without squeezing your face.
• The mask should not leak. A small amount of water seeping into the diver's mask is normal. But you don't want a steady stream. It will spoil your dive.
• Your dive mask should provide a clear window underwater. Masks come in a variety of shapes and styles for the face plates. If you're a beginner try different ones out. You may even want to buy a less expensive one at first to see if you like the style and design.
• It should be easy to adjust the pressure on your scuba mask as you ascend and descend. You do this by exhaling through your nose. The smaller the airspace, the easier it is to adjust the pressure.
• It's always a good idea to try on masks at your local dive shop. If you want to get the best deal, you may want to see, touch and try on the masks at a local shop, then order the one you like online. You are likely to get a better deal.

Choose a BC That Fits Your Diving Needs
The more you know about your buoyancy compensator, the better control you will have in achieving diving buoyancy or staying at a constant depth.
Choosing a buoyancy compensator that fits snugly and is comfortable to wear is important for an enjoyable dive. You also need to pick the BC that fits your diving needs.
There are three primary types of BCs:

• Wings, which are attached to a back plate. Wings have high buoyancy and often are used in technical diving. Just like a bird's wings, the inflatable bladders are positioned behind and to the side of a diver. Wings are not for everyone. They may float the diver face down, posing a danger in a life-threatening situation.
• Stab jackets, or vest BCs. The inflatable vests are comfortable to wear, fitting around the upper torso. They also serve as a cylinder harness.
• Adjustable buoyancy life jackets. Also known as horsecollar BCs, they are worn around the neck and chest. These older-generation scuba BCDs are inexpensive, but divers sometimes find the straps that secure them uncomfortable.

Technical Diving Poses Special Risks, Challenges Technical diving is a step beyond recreational diving that demands specialized training and skills. Technical diving also poses more risks and challenges for the scuba diver.
So what is technical diving? It often is defined as deep-water diving that requires decompression stops and special breathing mixes.
Technical dives are done at depths greater than 130 feet or in areas, such as caves, that have no direct access to the surface.
Technical divers have so-called controlled ascents after a dive, in order to make decompression stops along the way. The stops allow dissolved gases to be released gradually from the body and prevent decompression sickness, or the bends.