There are so many reasons, divers need to have and use dive reels or spools underwater.
One reasons is to send a delayed surface marker buoy up, to show the boat captain where you are.
Whenever you enter cave system and want to know the way out.
Penetrating an unknown or unfamiliar wreck.
For extra safety, you may need to carry two or sometimes multiple, reels or spools
A dive reel has a winder, typically more bulky, holds a lot more line, and easy to retrieve large amounts of line.
A finger spool is just that- a spool!- requiring more practice and careful use, to unwind and retrieve the line.
Reels are a crucial safety item for any Scuba Diving kit.
Reels are commonly used to lay guidelines through wrecks or caves and for surveying.
A scuba diving reel will typically have both a winding mechanism and a grab handle.
Winders make retrieving lines, quick and easy
Enclosed reels helps limit tangles, overruns and knots, when un-winding.
Reels are essential tools for divers.
They can be used to keep you in contact with surface support,
Guide you back to a known starting point
Indicate your position during search and retrieve operations.
Probably the most common application for a reel used by recreational divers is for the deployment of a delayed surface marker buoy or DSMB.
Should be relatively easy to release the line, to avoid snagging or tangling.
Small and compact spools should be able to fit into the smallest of pockets
Remember, Dive spools do require time and practice in order to become proficient, in their use.
Caution should be exercised when wearing thick neoprene dive gloves.
Finger spools are ideal for shallow deployment of a DSMB,
Jump reels can be spooled higher quantities of line, usually around fifty metres or so, to connect a diver from one already laid transit line inside a wreck to another line, leading out of the wreck or cavern.
Enclosed wreck reels are great for wreck and cave divers venturing into unknown, silty or overhead environments.
Wreck and or Cave reels have a capacity of one hundred plus metres of line.
Overhead divers often add colours or line arrows to their lines, to identify themselves.
Wreck reels need to be tough, made from Nylon, Delrin,or stainless steel.
Reels come into their own when they can be locked off when tying off, around pieces of the wreck or cave.
Essentially the most important thing is, not to get the line tangled!
Large capacity reels are the preferred choice of cave divers.
These reels can hold as much as 1000 metres of line, although 100 to 200 metres is a more manageable amount. Ideally the line needs to be light in colour — white is the chosen favourite for visibility in silty conditions — made of either 24 or 36 gauge negatively buoyant braid.
Line arrows enable divers to mark specific directions of travel.
Line cookies also help you identify your markers and route or mark a point of interest along the route.