Diving reels are a type of safety line, similar to what some contractors and rock climbers use. Diving reels, however, offer an extra layer of safety for divers who are diving in dangerous waters. Often used by wreck divers, cave divers, and technical divers, reels can come in handy for just about any diver who needs a little extra insurance on a riskier dive. Reels work like Ariadne’s thread in the famous Greek myth. Divers entering a dangerous area will unravel the line and head in, tying off their lines at specific points to avoid tangles. When it is time to head back, divers can simply retrace their steps to safety by following the line back. In addition, reels can also help divers signal to their crews onboard a boat or can be used to lift bags and other gear.

Since reels are a safety item, you will want to select your reel carefully. When choosing your reel, look for:

1) Simplicity. The more gadgets and additions your reel has, the more things can break down. Keeping things simple with a good line, handle, and spool safeguards your safety a little more.

2) A good line. Many lines are made from braided nylon, which is very strong. This is vital, because your line could come into contact with jagged rocks or sharp objects on a cave dive or wreck dive. When this happens, you want to make sure that your line stays intact.

3) Line size. Line sizes include, from smallest to largest, #24, #26, #36, #48, and 1/8-inch. You need to choose the line size that is appropriate for your needs. In many cases, you will need to balance weight against length. The longer your line needs to be, the thinner it will need to be to fit on your reel. In turn, the thicker and stronger your line is, the heavier and more cumbersome it will be. The fine #24 line, for example, is ideal for cave dives and other situations where you need length more than strength. For wreck diving, however, you will need a stronger #36 or #48, since a #24 line would likely break. Technical divers often use a 1/8-inch line, but this requires a larger reel in order to keep the line on the reel.

4) Reel size. Your reel size will depend largely on your line. A  4-inch reel, for example, will usually be able to handle 110 feet of 1/8-inch line, 250 feet of #48 line, 300 feet of #36 line, or 400 feet of #24 line. A smaller 3-inch reel will handle 100 feet of #48 line, 175 feet of #24 line or 130 feet of #36 line. A larger 5-inch reel will be bulkier and heavier but will be able to handle 800 feet of #24 line, 250 feet of 1/8-inch line, 550 feet of #36 line, or 425 feet of #48 line.

5) Winding. Consider how your line will be wound onto the reel. Generally, you have the choice between finger spools and winding knobs. If you dive in cold water or wear thick diving gloves, opt for a winding knob, which will make your reel easier to wind.

6) Tension control. Many good-quality reels feature a spring mechanism offering tension control. This is a very nice feature, especially if you are going to be using your reel to lift bags or other gear. The tension control will prevent your line from unwinding and will give you more control over how quickly or slowly the line unwinds from the spool.