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Overhead Environments: Cave vs. Advanced Wreck



By John Bentley

Being underwater is a ton of fun. Being inside things that are under water can be even more fun. Seeing the galley or crew quarters inside of a World War II-era shipwreck, or unique clay banks deep inside an underwater cave is an awesome experience.

The risk of not having a direct ascent is the same regardless of the environment. A simple problem that’s easily remedied in open water can be a serious problem when inside a structure, cave or wreck. Let’s take a look at what sets these environments apart.


Caves and wrecks offer the same general hazards for the scuba diver: That is, no direct access to the surface, crucial navigation and gas planning requirements.

Wrecks are more notorious for the hazards of rust, fishing line and cables. These entanglement and entrapment hazards are unique to wrecks as they deteriorate significantly faster than most cave environments.

Caves are not safer for entanglement and entrapment hazards though. While fishing line and cables don’t pose a risk in most caves, cave rock can be extremely sharp in some parts of the world, and being stuck against solid rock is less forgiving than rusted metal.


A major difference in cave and wreck environments is the distance traveled. It’s not uncommon for a cave diver to swim 600 m/2,000 ft into a cave system, a round trip of 1,200 m/4,000 ft. Wreck penetrations, even the long ones, are typically much shorter. Longer wreck penetrations off more twists and turns than typical cave dives, as sunken ships aren’t conduits for waterflow, they’re conduits for people flow and storage.


There are cave dives that require boats and wreck dives that are shore entries. Cave dives that are comfortably warm and frigid cold wrecks. Both can offer current, deep depths and even wildlife interactions. Some caves require proficient line work and dry caving skills. With all that in mind it’s fair to call the wrecks and caves equal in terms of harshness of logistics.

To line or not to line?

A diver can get lost in both caves and wrecks. Navigating in zero visibility or crystal clear-water without a reference is not a situation any diver wants to be in. Using a guideline properly is the best method for a “no thought” process of exiting overhead. Proper guideline use includes where to run the line, but more importantly, where not to run the line. Avoiding line traps, awkward following paths and sharp metal ensure that the line can be followed in zero visibility. That is the entire point of running line.

Wrecks typically have closer and more plentiful exits, which is why it’s popular to not run line as often. Many wreck penetrations are just long swim throughs, with a clear exit on the other end. An experienced wreck or cave diver will tell you without hesitation that you never trust an exit unless its verified.

So, what’s the take away? While one is gnarly twisted metal and the other ancient worn rocks, both environments offer similar hazards. They both are well worth the training to experience, and can stun divers with challenges and views.

Are you ready to move into to cave or advanced wreck diving? Check our Intro Cave Course here and our Advanced Wreck Diving Course here!

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.

Dive Training Blogs

Reef Rescue Network launches new interactive map



The Reef Rescue Network (RRN) was established in 2017 by the Perry Institute for Marine Science (PIMS) as a network of non-profit organizations and for-profit businesses committed to improving the condition of coral reefs by restoring populations of corals and other species that will build coral reef resilience. Since then the RRN has grown to include nearly 30 coral restoration sites in partnership with 25 local partners from 9 islands within The Bahamas as well as Aruba and St. Lucia. Through this partnership between coral reef scientist’s local conservation and education organizations and private businesses in the dive industry, the RRN is making significant advances in restoring coral and building reef resilience.

Visitors and locals can now immerse themselves in coral restoration activities at a partner location within the Reef Rescue Network. The network has coral nurseries that offer coral restoration experiences throughout The Bahamas, Aruba & St. Lucia. PIMS has developed a PADI Reef Rescue Diver Specialty Course that dive shops throughout the Reef Rescue Network are teaching. To participate, you must be a certified open water diver and at least 12 years old. The course takes one day and consists of knowledge development and two open water dives at a coral nursery.

You can learn how to assist with maintaining the nursery and get a hands-on experience or you can just scuba or snorkel the coral nursery as a fun dive to just observe and enjoy the nursery and marine life that it attracts. Another option is to scuba or snorkel one of the many restoration sites to view the corals that have been outplanted and witness for yourselves this habitat restoration and the marine life it has welcomed.

To find out more about the Reef Rescue Network, watch this video:

To visit the new Reef Rescue Network Interactive Map click here.

To learn more about the Reef Rescue Network visit their website by clicking here.

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Dive Training Blogs

Saving Scuba: Are We Living The Dream Yet?! (Watch Video)



Are We Living The Dream Yet?! How do we save scuba diving? A multi-million dollar industry primarily comprised of mom-and-pop shops. Non-essential. Tourism-based. And hit so hard by the Covid-19 pandemic.

In this video, I identify three key challenges to the scuba diving industry that have been amplified, but not created, by the coronavirus outbreak. Cute hashtags are not going to save scuba diving. We need a plan. We need action.

I have friends – professionals in the industry – who are suffering hardships because of this pandemic. And just because the quarantines may be lifted, it doesn’t mean everything will return to normal. People who have suffered economically because of business closures are not going to rush out and spend money on dive gear and travel.

As always, stay safe and thanks for watching. D.S.D.O, James

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Sharks Bay Umbi Diving Village is a Bedouin-owned resort with stunning views and a lovely private beach. It is ideal for divers as everything is onsite including the resort's jetty, dive centre and house reef. The warm hospitality makes for a diving holiday like no other. There is an excellent seafood restaurent and beach bar onsite, and with the enormous diversity of the Sharm El Sheikh dive sites and the surrounding areas of the South Sinai, there really is something for every level of diver to enjoy.

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