THOUGH WE RARELY REMIND you of it, many of the skills features we publish in DIVER are intended as a supplement to proper training, as a taster or reminder to highlight or add detail to some key points.
We don’t want to bore you by publishing government health warnings on every page. Nevertheless, there are times when the importance of proper training really has to be stressed.
Laying a line to aid return to a shotline in open water is a task to which any suitably experienced diver can apply these techniques. However, laying a line in order to venture into an overhead environment such as a wreck or cave is an application where training is absolutely essential.
This is pretty much paraphrasing what instructor Richard Walker said to Vobster Tek-Camp attendees last year when providing his half-day introduction to line-laying, on which this feature is based. Richard stresses that this is just an introduction and not intended as a substitute for a full overhead-environment training course.

While you could use any reel or spool to lay and retrieve line, it’s a lot easier with a reel designed for the job. The ratchet-reels that most divers use with an SMB are not favoured for line-laying, because you would have to hold the ratchet down all the time just to let line out.
More convenient is a free-running reel with a screw to lock it or adjust friction. The handle should be positioned so that a thumb or finger can also be applied to the rim to control friction.
Another key feature for any good reel is that there is no gap between spool and backplate that could swallow line and cause a tangle. It amazes me how many basic sport-diving reels have such a trap.

To go with one or more reels, a diver also needs some clips – to secure an unused reel to a spare D-ring and to act as an additional lock on the reel.
The favoured type are P-clips, also known as bolt-snaps, which come in single- and double-ended varieties.
P-clips can’t accidentally swallow line, as a spring-clip can. More importantly, they can’t accidentally swallow a line around which they are clipped, and consequently come loose.
Nevertheless, when attached to something solid like the body of a reel, a P-clip can still roll itself undone if clipped-in the wrong way round.

The good news is that the grade of line that comes with most diving reels and spools is perfectly suitable for laying, though some divers prefer a thicker line for handling or abrasion resistance.
One end should be secured to the drum of the reel, while the other has a loop tied or spliced in it. This loop can be used to make the primary belay without having to tie knots under water.

The primary belay or tie-off secures the line before entering an overhead environment. In rock-climbing, if you fall on a rope the primary belay needs to be strong enough to take your
weight. When diving into an overhead environment, it needs to be strong enough that it can’t pull free if a diver pulls himself back on the line.
After wrapping the end of the line round whatever solid point has been selected, the reel is passed through the loop to secure it without any need to tie knots under water. The line can then be wrapped a few more turns round the belay point to ensure that the line is taking any strain, and not the loop.

The secondary belay is a good solid tie-off just inside the overhead environment, with the line wrapped a couple of times round, and then secured on, another solid point. In this way any further stress on the line is taken by the secondary rather than the primary belay. Again like climbing, the primary belay should never be stressed.

From here on in, the line needs to be secured whenever the direction changes, and every so often for good measure.
It should be laid low enough that divers can remain above it, and ideally far enough off the bottom that disturbance of silt is minimised.
The line should be laid so that it can’t pull into cracks that would prevent it from being directly followed. Belay points should be strong enough that they can’t pull free. But all of this is an ideal and any dive may require compromises to be made.
Judging when, where and how to tie off is one of those things that comes only with training and experience.

At some point, divers will decide to turn round, perhaps because gas-planning dictates turning round, or because an objective has been reached.
So what then happens to the line Perhaps it will be rewound, or tied off and cut from the reel.
Perhaps the reel will be left in place, ready to be picked up and continued with on a later dive. In this case in addition to the final belay, the reel needs to be secured by wrapping back round the line and clipping with a double-ended bolt-snap, remembering the direction in which to clip the bolt-snap to prevent it from being pushed open.

While everything so far has been about laying a line, this is a skill that will be trained for, but not actually used in a diver’s first few ventures into an overhead environment.
Before a diver can lay new line, he has to gain experience in simply following a line, either laid by his buddy and leader on a dive, or laid previously by other divers.
Many established cave-diving locations have line permanently laid for just this purpose.
Even following a line is not as straightforward as simply swimming alongside it. There are skills and conventions to learn and repeatedly practise until they can be applied automatically.

Whenever visibility could be called into question or is at risk, divers need to maintain physical contact with the line. A simple thumb and finger ring is not reliable enough – a jerk against the line could pull it out between the thumb and fingertip.
Instead, a ring is formed by locking the thumb between the first and second fingers, so the tip of the thumb is actually gripped between the two fingers.
The thumb edge of the hand always marks the direction of travel, which for beginners at the overhead environment game would be towards the exit when visibility is reduced to zero.

When passing a belay, one hand needs always to be locked to the line with the correct grip pointing the direction of travel. The other hand can feel round the belay, establish where the line continues, and make the direction-pointing grip on the far side of the belay before the first hand is released to resume the grip past the belay.
The key is that the diver always has one hand on the line with a direction-pointing grip.
Failure to maintain this simple procedure in low visibility could lead to the line being lost, or the direction becoming reversed and divers turning back into the overhead environment, when they should be heading back out!

In general, a line should be laid so as to minimise any need to cross it.
Nevertheless, practicality of placing belays means that sometimes the line will need to be crossed, usually close to a belay point.
The line should always be laid to enable a diver to cross over it, and never beneath it, because that involves far less risk of entanglement.
Crossing a line usually involves a change of the hand following the line, so the direction-pointing grip has to be maintained as the line is crossed.

When the time comes to turn around, the order of the group following the line swaps about. Last man in becomes first man out.
However, there could be exceptions, where divers swap roles during a long dive, or during gas-sharing, where the out-of-gas diver precedes the donor out of the overhead environment.

Line-laying is just the most obvious component of the range of skills involved in cave- or wreck-penetration.
Other new skills and extension and refinement of many existing diving skills are involved. The answer to these unknowns is to do appropriate training.

TekCamp:; Vobster: