Thirteen per cent of divers have lost weights; 9% have lost the whole belt. So what's going wrong and what can be done about it? asks Robert N Rossier.
SURPRISES MAY BE FINE ON BIRTHDAYS and other special occasions, but when it comes to diving, most of us prefer to limit the surprise factor.
One of the most unwelcome surprises in diving is a sudden change in buoyancy, or not having the ability to make such a change when needed.
Despite the relative simplicity of weight systems, divers do on occasion suffer weight-system-induced surprises, and the consequences can be more than trivial.
Consider the case of an instructor and two students who descended a shotline to dive a wreck in 2006. On reaching 7m they adjusted their equipment, then continued down to 19m.
As the BSAC Incident Report reads: “At this point, one of the trainees lost her weight-belt and began to make a buoyant ascent. The instructor took hold of the trainee and made himself negatively buoyant. They then made their way along the wreck back to the shotline.”
Fortunately, the instructor and trainee were able to make a controlled ascent up the line, and were recovered to the boat uninjured. Thanks to the instructor's quick response, the situation was remedied.
In December 2005, three divers had done a dive to 36m and, with six minutes of deco time required, one had deployed a delayed SMB and initiated an ascent.
According to the BSAC report, “one of the divers' weights fell out of its pouch, and despite finning downwards to slow his ascent, he was carried rapidly to the surface.”
The diver was recovered to the boat, put on oxygen, and given fluids. Fortunately, no further problems or actions were reported.
Perhaps more chilling is the situation that developed for two divers on a shore dive last September. Some 60 minutes into the dive, one discovered that her BC was dumping air, and she was no longer able to manage her buoyancy.
“She tried to remove her weightbelt, but it became entangled around her wrist,” stated the BSAC report.
Still unable to release her weights, the two reached the surface in 6m of water and called for assistance. They then managed to move into shallower water, where both succeeded in removing their weights, and a local fishing boat helped them to shore.
It was thought that the diver's BC valve was faulty or jammed. Neither diver suffered any injuries.
But weightbelt problems can be fatal.
In a case reported in DAN's Report on Decompression Illness, Diving Fatalities and Project Dive Exploration in 2004, a 50-year-old divemaster was diving a wreck with two buddies at 37m when something went horribly wrong.
The three had started their ascent, but became separated on the way up. The diver's body was recovered by another group of divers some 10 months later.
According to the report: “The body was entangled in the wreck, and the deceased had removed his weightbelt, but it had become entangled in his catch-bag.”
The report notes that the diver was morbidly obese, but does not indicate whether this may have been a factor in the fatal accident.
These reports remind us of the importance of reliable weight systems.
To learn more about them, and the difficulties that divers encounter, Scuba STAR Network conducted an online safety survey. Nearly 300 divers responded.
We asked about diving habits – including maintenance and pre-dive safety checks – as well as misadventures with weight systems.
The results of the survey told us a few things we already knew, but held a few surprises as well.
NO STANDARD GEAR
Gone are the days when every diver wore a conventional weightbelt – a nylon web belt with a quick release designed to ditch the lead should immediate buoyancy be required.
Only a quarter of those surveyed use a conventional-style belt, and one third of these use pocket belts rather than the old standard lead-on-web design.
Seventy per cent of divers now use weight-integrated BCs, with a near-even split between those with single weight releases and those with multiple releases.
About 4% surveyed use weight harnesses, which distribute the weight with webbing over the torso, and incorporate a weight-release mechanism similar to the weight-integrated BC design.
One of the most dangerous situations arises when a diver is suddenly and unwittingly unlatched from his weights.
Sadly, this happens to one in four divers, with the clear majority of cases occurring beneath the surface.
While many divers resolve such a situation without incident, others are less lucky.
According to the survey, roughly 20% of the divers who suffer the indignity of a lost weight or belt under water end up making an unscheduled, direct ascent to the surface.
Attendant in such a situation is the risk of decompression illness, especially if the diver has exceeded the no-stop deco limits and had planned on making a stop.
DROPPING THE LEAD
Very few divers (4%) report that they have ever dropped their weight intentionally, but on those rare occasions when getting the lead off was necessary, more than one in 10 experienced difficulties.
Half couldn't find the release, and the rest had problems either with operating the release, dropping all the weight, or with the weights becoming entangled.
Considering the conditions under which a diver decides to ditch his weights, any such complications could represent a serious hazard.
While 75% of the divers report that they never have problems with their weight systems, the remainder report a variety of glitches. As shown in the table, shifting belts and a need for frequent adjustments are common maladies.
So it's perhaps no surprise that divers report not being able to find the release, or not being able to release the weight when needed. Surprisingly, 1 in 8 (13%) report that they have lost a weight from a belt or pocket, with 9% stating that they have lost their belts entirely.
Clearly, if divers want some confidence that they can drop their weights when needed, it's important for them to check their systems thoroughly.
Most report doing exactly that. More than nine in 10 say they check their weight systems either for every dive or for almost every dive.
Nearly 90% perform a function check of their weight system before most or all dives, and the same number report that they check its condition before most or all dives.
Naturally, the details of this check depend on the type of belt, but it appears that among the most important checks are condition and function of the buckle or release, and security of weights.
As the data points out, other items such as the condition of the stitching can also be critical in assessing the seaworthiness of a weight system.
Despite any common appearances, there are significant variations among weight systems produced by different manufacturers.
In one incident report made to Scuba STAR Network, a diver reported that after having the wrong amount of weight on his belt for his first dive of the day, he switched to a different belt that had the proper amount.
The problem was that the second belt had a plastic buckle, and the teeth that grip the nylon webbing to secure the belt were well worn.
The buckle gave way on the second dive, releasing the belt and causing the diver to make an unplanned ascent from 22m.
Fortunately, the diver did not suffer any injuries, although it's unclear where his buddy was at the time.
Divers should purchase equipment made from high-quality materials, and check the condition of their buckles or weight-release mechanisms regularly – if not before every dive.
Bent or damaged buckles, worn teeth and worn nylon webbing could be signs of trouble, and should be replaced.
Another crucial wear item is the Velcro used in many systems to secure weight pockets and other components of the weight system.
Repeated use over a long period can cause significant degradation of the attachment's holding capacity, increasing the chances of inadvertent weight loss.
Quality of the stitching is another issue with pocket belts and other systems. Inferior stitching on pockets can easily unravel, allowing weights to fall out.
Proper rigging is another key issue. When using a conventional weight-belt, divers should put a twist in it or use a weight clip to stop the weight sliding.
Too little or too much tongue overlap can also be a problem. If the belt is too short, the diver might have difficulty making the necessary adjustments to belt tension during descent, and may accidentally lose the belt in the process.
With too much tongue overlap, the excess may become entangled and cause accidental release, or become wrapped up and prevent the belt being ditched.
Divers need to wear their weightbelts properly, with no other straps covering the belt, and with the buckle release facing in the correct direction.
The Scuba STAR Network safety survey isn't the first to focus on problems with weightbelts and systems, but it's an important reminder of the issues involved.
Roughly a decade ago, the Australia-based South Pacific Undersea Medical Society (SPUMS ) initiated its Diving Incident Monitoring Study (DIMS) to evaluate issues in diving safety.
According to its report, weightbelts rank fourth in the list of equipment-related incidents and accidents, and were implicated in 7% of the first 1000 equipment-related incidents and accidents reported.
Weightbelts were also involved in 12% of the reported injuries.
Among the recommendations made by the DIMS report were five training concepts that could help reduce the number of weightbelt-related incidents and accidents:
- Conduct training in how to control a rapid ascent.
- Emphasise proper securing of the weightbelt.
- Always verify that no other equipment or straps overlap the weightbelt.
- Teach correct techniques for handling weightbelts at the exit point.
- Teach proper technique for jettisoning the weightbelt – holding it away from the body so that when it falls it is clear of all other equipment.
As weight-integrated BCs become more popular, instructors and training agencies should update their programs to address the needs of this type of equipment as well, and provide a level of training commensurate with the application of new types of equipment.
Divers should be made aware of different types of weight systems, and how their release mechanisms operate.
Buddy checks should include verifying that each diver knows how to release his buddy's weights.
Weightbelts and weight systems are not complicated devices but, as anecdotal evidence suggests, they can seriously complicate a dive when they don't perform as expected.
By focusing on a few basic concepts, we can limit the potential for weighty surprises.
Find more results from Scuba STAR's Safety Surveys at their website.
PROBLEMS WITH WEIGHT SYSTEMS
|% DIVERS EXPERIENCING
|Shifting weight or belt during dive
|Belt requires frequent adjustment
|Loss of weights from belt or pocket
|Loss of weightbelt
|Unable to release weight (all)
|Unable to release weight (partial)
- Inspect your weightbelt or weight system before each dive, checking the condition of stitching, closures and buckle.
- Before diving, check that weight-release mechanisms are working correctly.
- Verify that all weights are secured according to manufacturer recommendations. Don't dive with suspect closures or attachments.
- Excess strap should be in the 15-20cm range.
- Wear conventional weightbelts with the release oriented in the proper direction.
- Ensure that no straps cross over the weightbelt.
- Avoid placing weights in BC pockets or other locations where they can be easily dropped or dislodged.
- During descent, as your suit compresses, check tension on the belt to make sure that it doesn't slip or rotate.
- Check that your buddy knows how to release your weight in an emergency.