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That’s wrong: misconceptions about overhead diving



By: John Bentley & Brian Shreve

The interwebs are a great place to pick up some great, and some not so great, information.  Internet cave divers seem to enjoy spouting off opinions based loosely on nothing. This is particularly scary considering the fragility of the cave community and the necessity for standardization in cave diving. Spend a little time on the various scuba related websites, and it’s amazing some of the just plain wrong things you can read!

Here are just a few of them we’ve recently found:

The Rule of 1/6th isn’t appropriate for gaining real experience

This is, unfortunately, a popular one in the North Florida area: The idea that 1/6th doesn’t give the Intro Cave diver enough distance to utilize their newfound awareness, conservation and buddy skills. That’s just not the case. 1/6th gives adequate gas, even for the biggest gas guzzler, to get acquainted to a cave system in a way that exposes them to overhead stress with emphasis on line awareness, buddy procedures, communication, and gas management. It essentially eliminates navigation stress through mainline navigation only, reduces time/distance stress and eliminates most decompression obligation stress.

If 1/6th diver’s gas consumption rates aren’t adequate for getting a few hundred feet into the cave that shows that their comfort level, fitness, and streamlining are not to the level needed to be that far into a cave anyway. While all divers breathe at different rates, and that’s a physiological issue, even the best trained divers double their gas consumption rate under stress. Putting a high volume breather further into a cave without mastery of stress management is asking for trouble.

Visual Jumps are OK

It’s only 3 feet!
This cave never silts out!
I’m familiar with this passage…

Holy moley, no! This one defines all logic. The time it takes to install a jump or gap, a matter of seconds, nullifies all reasons that this would be ok. All overhead dives should be planned for a total loss of visibility, whether through siltation, total light failure or mask loss. If viz is gone finding the gap will be difficult, objectively more difficult than following a line.

Primary lines are optional in tourist caves

This system will spit me out if I’m lost!
Close to open water is close enough!

This one goes back to the previous point. Just no! Tourist caves, like Ginnie and Peacock, that don’t have a line that goes to open water, are no safer than a virgin system. A cavern full of students can quickly make Peacock impossible to navigate. Plenty of individuals have perished in the forward section of a system because they couldn’t clearly find an exit. Just to clarify – If you’re in trouble, running low on gas after a reg failure in low vizibility, do you really want to hit the end of the line, let go, and hope for Mama Ginnie to spit you out? If the answer to that is yes: please, please, take up racquetball instead of cave diving.

It annoys everyone when caverns are a mess of lines, and yes, sometimes that makes it more dangerous. The only solution for a clear exit, where the line runs to the open water, is for cave divers to speak up and have lines extended to open water. This is an issue with land owners not properly restricting access to non-overhead divers. If the site is not open water appropriate (Ginnie for example) then it needs to be restricted to overhead divers only and the guideline should be extended to open water to prevent too many lines. Issues like this are very isolated to certain sites in North Florida and, despite the ease of fix, have spawned an alternate pattern of thinking towards continuous guidelines in cave diving. While every cave is unique and beautiful no cave merits entry without the ability to very easily navigate to the surface with visibility loss.

The Rule of 1/3rds is always appropriate

This is normalization of deviance at its best. The rule of thirds is not always appropriate. When exerted you will use substantially more gas. Long strenuous swims using substantially more gas, or possibly gas sharing, will not work with the rule of thirds. Stages do cause drag and aren’t always appropriate but with long swims in low flow systems they’re a necessary parachute. The “Grand Traverse” in Peacock is often done on thirds and while that seems appropriate to some the margin for error is little with only the gas in a couple sets of mains. A setup dive for longer swims or scooters should include a stage cylinder(s) drop for use as a safety cylinder. This goes back to the basics of dive planning and gas management. We’ve seemed to have forgotten that there are reasons behind the 1/3 rule.

These are just a sample of researched and proven techniques being put to the wayside for stories being shared between divers. The data pools aren’t huge in cave diving, but they’re large enough to set our safety standards. Ignoring these basic guidelines puts us all at risk.

To find out more about International Training, visit

From its humble beginning in 1994 to today, the group of training agencies Scuba Diving International (SDI), Technical Diving International (TDI), and Emergency Response Diving International (ERDI) form one of the largest diving certification agencies in the World – International Training. With 24 Regional Offices servicing more than 100 countries, the company today far exceeds the original vision the founders had when they conceived the idea on a napkin, sitting at a kitchen table in the early 1990’s.


Get moving with the new RAID DPV training programs



The thrill of speeding through the water behind a diver propulsion vehicle (DPV) is an experience that really gets the blood racing. Using a DPV provides divers both immense fun and the means to achieve goals that would be impossible without their use.

RAID is proud to announce the new two-tier DPV training program with certifications for DPV and Advanced DPV.

Why DPV and why now?
Recreational and technical divers are using DPVs to access sites that would be difficult to reach and explore using traditional propulsion methods; to help propel large amounts of heavy equipment; to increase the safety of dives in areas of strong current; or just for the pure exhilaration of shooting through the water at speed and performing underwater acrobatics.

By extending your capabilities and extending your range, using a DPV opens new vistas for exploration and fun.

This certification option is aimed at the recreational diver who wishes to learn how to use a DPV to enhance their diving by using mainly natural navigation.

Advanced DPV
This certification option is available to anyone who is familiar with longhose configuration, has logged a minimum of 20 dives and is certified as Navigation specialty divers.

This certification option is aimed at the slightly more experienced diver with preexisting navigational training and diving on a single, twin or sidemount setup with a longhose. Although this level is slightly more challenging, the more advanced navigation exercises provide an important base for more complex types of DPV diving within a team.

You must:

  • Be a minimum of 12 years old.
  • Be certified as RAID Open Water 20, Junior Open Water or equivalent.

Just visit to put some extra dash into your dives.

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Marine Life & Conservation

Beers raise cash for ocean clean-up



The Driftwood Spars Brewery, a pioneering microbrewery based on the North Cornwall coast, is donating a percentage of all profits from its Cove range of beers to Fathoms Free, a certified charity which actively cleans the ocean around the Cornish peninsula.

Each purchase of the small-batch, craft beers – there are four different canned beers in the Cove range – will help generate funds to purchase a remotely operated vehicle (ROV) and fund retrieval dives; every brew will raise the equivalent cost of a fully-funded dive. 

Fathoms Free is a Cornwall-based charity whose day-to-day mission involves dives from their fast-response specialist vessel to recover ghost fishing gear; abandoned nets, pots, angling equipment and other plastic causes severe damage to the marine environment and the death of countless seabirds, seals, dolphins and other sea life.

The campaign to raise funds for an ROV is a new initiative which will take the clean-up work to a new level; the highly manoeuvrable underwater vehicle will be used to scour the seabed, harbours and remote parts of the coastline for abandoned fishing gear and other marine litter.

Project Manager Natallia Paliakova from Fathoms Free said: “Apart from helping us locate ghost gear underwater, the ROV will also be capable of recording underwater video which is always great for raising awareness about marine pollution issues.”

She added: “We are really excited to be partnering with The Driftwood Spars Brewery and appreciate the proactive support of Mike and his team in bringing the purchase of an ROV a step closer to reality.”

Head Brewer Mike Mason personally approached the charity after their work was featured on the BBC 2 documentary, ‘Cornwall with Simon Reeve’.    

He said: “As a keen surfer I am only too aware of the problem of marine litter and had heard about Fathoms Free, but seeing them in action prompted me to find a way of contributing. The scale of the challenge is scary, but the determination of organisations like Fathoms Free is inspiring.”

Photo by Beagle Media Ltd

Photo by Beagle Media Ltd

The Driftwood Spars Brewery was founded in 2000 in Trevaunance Cove, St Agnes; the microbrewery is just a few steps away from it’s co-joined brewpub, The Driftwood Spars; both pub and brewery are well-regarded far beyond the Cornish cove they call home. 

You can hear the waves and taste the salt on the air from the door of both brewery and pub, and the rough seas along the rugged North coast often throw up discarded nets and other detritus; Louise Treseder, Landlady of The Driftwood Spars and a keen sea swimmer, often collects washed up ghost gear on her daily beach excursions.     

Louise commented: “This is a great partnership to support a cause close to our hearts – I know the money we raise will have a positive and lasting impact. The Cove range was inspired by our unique surroundings and the artwork – by local artist Jago Silver – reflects that. Now donations from each purchase will contribute towards the vital ocean clean-up taking place right on our doorstep.”

The Cove range can currently be purchased online here, and is available in good independent bottle shops in Cornwall.

To find out more about Fathoms Free visit their website here.

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This is the perfect start to your 2021 diving season… and at an incredible lead-in price of just £885 per person.

Jump on board the latest addition to the Emperor fleet and enjoy diving the famous sites of the Red Sea with this fantastic special offer. This itinerary takes in the wonderful South & St Johns from 26 February – 05 March 2021.  

Subject to availability – limited flight seats at this price so don't delay!

Call Diverse Travel on 01473 852002 or email to book your spot!

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