1At a glance
- Primary Uses
- SMB deployment, navigation, guideline, search & recovery
- Common Line Lengths
- 15 metres (50 feet) to 120 metres (400 feet)
- Line Material
- Nylon, polyester, polyethylene (e.g., Dyneema)
- Line Diameter
- 1 mm to 3 mm (0.04 to 0.12 inches)
- Deployment Method
- Manual for spools, manual or mechanical for reels
- Weight (approx.)
- 50 grams (1.8 ounces) to 500 grams (1.1 pounds)
- Buoyancy
- Typically neutral or slightly negative
2How reels and spools work for divers
A diving reel or spool functions by storing a length of line in a compact and manageable form, allowing divers to deploy it in a controlled manner underwater. When deploying a surface marker buoy (SMB), the line is attached to the SMB, and as the SMB ascends, the diver carefully feeds the line from the reel or spool. This controlled release prevents tangling and allows the SMB to reach the surface while remaining attached to the diver.
For navigation, especially in overhead environments like wrecks or caves, a reel or spool is used to lay a continuous guideline from the entry point. The diver attaches one end of the line, then proceeds, unwinding the line as they go. This guideline provides a tactile reference for returning to the exit, crucial for maintaining orientation in low visibility or complex passages. The line is usually marked at regular intervals for distance reference.
Retrieval involves carefully winding the line back onto the device, ensuring it is neatly stored and ready for the next use. Reels often feature handles and locking mechanisms for easier winding and to prevent accidental line release, while spools require the diver to manually wrap the line around the core. Proper technique is essential to avoid line jams, twists, or accidental free-flowing of the line, which can create entanglement hazards.
3Reel vs. Spool vs. Finger Spool
| Feature | Diving Reel | Diving Spool | Finger Spool |
|---|---|---|---|
| Design | Handled frame with winding mechanism, often with drag/lock | Cylindrical core with end plates, no handle | Small cylindrical core with end plates, often with a central hole for a finger |
| Line Capacity | Moderate to large (30-120 m / 100-400 ft) | Small to moderate (15-60 m / 50-200 ft) | Small (5-30 m / 15-100 ft) |
| Ease of Deployment | Controlled, often one-handed with practice, less prone to tangles | Manual, requires two hands initially, can be prone to tangles if not careful | Manual, simple, good for short deployments |
| Primary Use | Guideline navigation, SMB deployment in current/depth | SMB deployment, short navigation/jump lines | Signalling, short jump/gap lines, marking locations |
| Cost | Higher | Moderate | Lower |
4What reels and spools mean for your liveaboard trip
Carrying a reliable reel or spool is a practical and often essential piece of equipment for divers on liveaboard trips. Many liveaboard itineraries involve drift dives or dives in areas with strong currents. In these scenarios, deploying a surface marker buoy (SMB) upon surfacing is critical for the crew to locate and pick up divers efficiently. A properly managed reel or spool ensures a smooth and safe SMB deployment, enhancing diver safety and minimizing surface time waiting for pickup.
Beyond SMB deployment, a reel or spool can be invaluable for liveaboard divers who engage in more advanced diving, such as wreck penetration or specific technical dives. It provides a means to lay a guideline for safe entry and exit from overhead environments, a skill often practiced and refined during liveaboard-based courses or specialty dives. Even for less technical dives, a spool can be used to mark a specific point of interest, like a unique coral formation or a small wreck, for other divers in the group or for future reference.
Before embarking on a liveaboard, divers should ensure they are proficient in deploying their chosen reel or spool and SMB. Practicing in calm conditions or during a checkout dive will build confidence and ensure readiness for the specific dive conditions encountered. Many liveaboards offer opportunities for advanced training, including SMB deployment skills, and having personal equipment ready to use can greatly enhance the diving experience.
5SMB Deployment Techniques by Reel/Spool Type
| Device Type | Common Method | Advantages | Considerations |
|---|---|---|---|
| Diving Reel | One-handed deployment from handle, using thumb/finger for drag control. | Controlled ascent, easy to manage excess line, quick retrieval. | Can be bulky, more prone to free-spooling if lock fails, requires practice. |
| Diving Spool | Hold spool with one hand, feed line with the other, allowing it to unwrap. | Simple design, compact, less mechanical failure points, good for short lines. | Requires two hands for initial deployment, more prone to tangles without care. |
| Finger Spool | Hold with fingers through central hole, feed line manually. | Very compact, simple, excellent for tight spaces or small SMBs. | Limited line length, can be tricky to manage with thick gloves, slow to wind. |
| Weighted Reel | Reel with integrated weights, allows for hands-free vertical deployment. | Very smooth, controlled SMB ascent, maintains vertical orientation. | Heavier, more specialised, less versatile for other guideline uses. |
| Safety Reel | Reel with built-in quick-release or anti-tangle features. | Minimizes entanglement risk, faster emergency deployment. | Can be more complex and expensive, requires familiarisation with features. |
6Common misconceptions
Myth: Spools are only for technical divers. Fact: While spools are widely used in technical diving for jump lines and navigation, they are also excellent tools for recreational divers for SMB deployment, especially the smaller finger spools. Their simplicity and compact size make them a popular choice for all levels of diving.
Myth: Any reel or spool will do for SMB deployment. Fact: Not all reels or spools are created equal. For SMB deployment, a reel or spool with at least 15-30 metres (50-100 feet) of line is generally recommended, depending on expected depth and current. It should also be robust, easy to operate with gloves, and preferably have a swivel or anti-twist mechanism to prevent line tangles during deployment.
Myth: You don't need a reel or spool if you dive with a dive guide. Fact: While dive guides are experienced, unforeseen circumstances can arise. Carrying your own SMB and the means to deploy it (reel or spool) is a fundamental aspect of responsible diving and self-sufficiency. It provides an independent way to signal the surface in an emergency or if separated from the group.
Myth: Reels are inherently safer than spools because they have a handle. Fact: Both reels and spools can be safely used if the diver is properly trained and proficient. Reels can sometimes 'bird's nest' if the line is not managed correctly, leading to jams. Spools, while simpler, require careful manual feeding to avoid tangles. Safety largely depends on diver technique rather than the device itself.
FAQ
What is the main difference between a reel and a spool?
A reel typically features a handle, a winding mechanism, and often a locking or drag system, making it easier for controlled deployment and retrieval. A spool is a simpler design, consisting of a cylindrical core with end plates, requiring manual winding and unwinding of the line.
Why do I need a reel or spool for diving?
Reels and spools are crucial for diver safety and communication. They are primarily used to deploy a surface marker buoy (SMB) to signal the boat or surface support, for navigation in overhead environments like wrecks or caves, and for marking points of interest underwater.
What length of line is typically needed on a reel or spool?
For recreational divers deploying an SMB, a line length of 15-30 metres (50-100 feet) is usually sufficient. Technical diving or specific wreck/cave navigation may require much longer lines, ranging from 60-120 metres (200-400 feet) or more.
How do I attach a reel or spool to my diving gear?
Most reels and spools come with a double-ended bolt snap or a similar clip. This allows them to be securely attached to a D-ring on your BCD, ensuring they are easily accessible when needed but out of the way during the dive.
Can I use a reel or spool if I haven't been trained?
While the basic concept is simple, proper training is highly recommended. Deploying a reel or spool, especially for an SMB, involves specific techniques to avoid entanglement, line jams, or rapid ascents. Many dive courses, such as the PADI SMB Distinctive Specialty or advanced courses, cover these skills.
Are reels and spools buoyant or negatively buoyant?
Most reels and spools are designed to be neutrally or slightly negatively buoyant when fully loaded with line. This prevents them from floating away if accidentally dropped and helps maintain control during deployment underwater.