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The GUE Pre-dive Sequence

As you’d expect, Global Underwater Explorers (GUE) has a standardized approach to prepare your equipment for the dive, and its own pre-dive checklist: the GUE EDGE. Here explorer and filmmaker Dimitris Fifis preps you to take the plunge, GUE-style.



By Dimitris Fifis
Header photo by Alexandra Graziano for Global Underwater Explorers.

GUE divers follow a standardized sequence to prepare for their dives. This sequence minimizes any possible mistakes or omissions that might affect the outcome of the dive; the sequence also serves as the last line of defense against any errors that may have been made while preparing equipment or filling tanks. The procedure helps the team “switch into dive mode” as they prepare for the fun ahead.

Before starting this sequence, all equipment should be assembled with tanks filled and analyzed, and with appropriate analysis marking completed. 

This general sequence is executed as follows:

Before all else, check your valves are open. Photo by Alexandra Graziano for Global Underwater Explorers.
  1. Open tank valve(s) completely. In the case of double tanks, be aware that one outside valve turns opposite to the other and that the isolator must be open. Check the SPG, and compare with expected pressure as well as that noted on the analysis sticker. 

2. If using a drysuit, ensure your drysuit zipper is fully closed and verify pocket contents are in place.

3. Don equipment, secure and tighten harness.

4. Don remaining accessories—if not done as part of donning equipment—such as necklace regulator and drysuit inflation hose (if a drysuit is used). Stow and secure primary light cord under harness, clip light head in permanent position on right chest D-ring.

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Check and secure the contents of your pockets before each dive. Photo by Alexandra Graziano for Global Underwater Explorers.

5. Route long hose regulator (primary) across the chest and around the neck. Secure second stage to right chest D-ring and secure excess hose length.

6. Perform GUE EDGE with the team.

7. Enter the water.

8. Perform bubble check. When conditions do not allow the team to safely perform a bubble check on the surface (due to waves or strong current), the check can be performed at shallow depth during descent.

9. Perform modified S-drill, ensuring long hose integrity. Modified S-drill should always be the last check performed; if it is performed prior to other equipment tests and manipulations, there is always the possibility of long hose entrapment (e.g., while connecting a drysuit inflation hose). 

10. Start the dive.


GUE EDGE is an acronym designed to help GUE divers follow a standardized pre-dive check. This review ensures that all team members are ready for the dive, that they all confirm understanding of the basic dive parameters, and that their equipment is ready and functioning as intended. It is usually performed prior to entering the water but it can be performed at the surface just prior to descent, if conditions allow (manageable waves, current). The procedure is led by the team leader with the team members confirming or stating all required parameters. 

If you would like to learn more about the pre-dive procedures you can purchase the “GUE Pre-Dive Sequence” Guide for less then $5 on 

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Born in Athens, Greece, Dimitris Fifis started diving in 1991 and became an instructor in 1998. In 2009, after 23 years of service in the Greek Navy (most of them in the Aviation branch), he retired and decided to pursue a full-time career in diving. Since then he has managed diving operations in various diving centers in Greece as well as on mega-yachts. Dimitris discovered GUE in 2007 and never looked back. He currently lives and works in Dubai, and is involved in various wreck exploration and underwater filming projects in the area. Because of his strong interest in increasing dive safety through quality education, he also produces training videos for GUE.

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GUE 25 Anniversary Conference Round Up




Global Underwater Explorers held a conference to commemorate the organization’s 25th anniversary. Held at GUE headquarters in High Springs, Florida, where it was founded by a group of cave divers founded in 1998, the organization convened instructors and divers from all over the world to recall the people and diving technologies that shaped GUE, how they’ve changed over time, and how they’ll evolve in the future.

In addition to celebrating the occasion, GUE convened speakers to present on topics related to its three biggest priorities: Exploration, Education, Conservation.

Shipwreck explorer Mario Arena, for example, gave a presentation on the “Battle of Convoys in the Mediterranean,” his 16-year project discovering and documenting dozens of shipwrecks left behind by the three-year-long battle during World War II and how his team is bringing the wrecks back to life using new technologies.

Cave explorers Fred Devos, Julien Fortin, and Sam Meacham gave a presentation on their efforts to document Ox Bel Ha, the largest underwater cave system in Mexico, a project which is concurrently celebrating its 25th anniversary. The project started out with, as Meacham called it, “two chainsaws, a compressor, and a horse,” and has begun to resurvey 144 square miles of caves with advances in diving equipment. Advances as simple as upgrades to lightbulbs and batteries, for example, enable the explorers to see through new passages.

Bill Stone, a cave explorer and head of Stone Aerospace, discussed “Recent Advances in Machine Exploration,” chronically how he’s used machines to explore underwater caves farther than any human. Stone’s autonomous drone, called Sunfish, uses sonar mapping to produce 3D maps and models deeper than photogrammetry divers can dive.

Ulrik Juul Christensen, a founder and chairman of Bonaire’s Area9 Mastery Diving Research Center, is developing an adaptive learning education platform for GUE and has spent about as much time as the organization has been in existence building education technologies. Christensen’s talk, “Learning That Matters,” focused on how to create new systems to help educate learners at their own pace so that knowledge, and not speed, is the priority.

In a complementary presentation, Sean Talamas, a managing partner and executive coach at leadership development consulting firm, discussed “The Depth of Character: Cultivating Grit, and a Growth Mindset.” The presentation focused on research by Angela Duckworth suggesting success is not achieved through talent, but a combination of passion and persistence she called “grit.” 

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GUE Instructor Trainer Andrea Marassich gave a presentation on “Building Capacity for Extreme Explorations” about the Sa Conca e Locoli Cave Project in Sardinia, Italy. Learning, he suggested, happens when you go out of your comfort zone, but not all the way to what he called the “panic zone,” where you are overwhelmed to the point that you don’t learn but instead shut down and it becomes extremely dangerous.” “You need a mentor,” Marassich said. “Someone who knows you enough to push you when you need to be pushed and pull back when you need to pull back.” 

These were just a few of the education- and exploration-focused presentations. Speakers also included Blue Green Expeditions Managing Partner Faith Ortins on how divers can support environmentally conscious destinations, Peter Gaertner on citizen science conducted in the Caves of Gulf of Orosei project, Daniel Ortego on the Marine Genome Project, and Neal W. Pollock on the physiological limitations of technology in diving. 

Max Deco & Bubble Trouble entertained conference attendees at the Friday night social with a pre-dive playlist of classic rock. Band members: John Kendall vocals, Gary Franklin vocals, Bill Stone lead guitar, Andrew Dow guitar, Francesco Cameli bass, Michael Menduno bass, Jason Cook drums.


You can find the full conference photo album here

InDEPTH: GUE’s 25th Anniversary Timeline-Picturing 25 years of Global Underwater Explorers.

InDEPTH: Twenty-five Years in the Pursuit of Excellence – The Evolution and Future of GUE

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