Why are Prerequisites Important in Technical Diver Training?

Prerequisites can be found in the Standards and Procedures for any course you are interested in taking.


Diving Casualties of War

by Steve Lewis:
TDI war tank wreck on ocean floor

It was veteran journalist and author Tom Brokaw who first coined the term “The Greatest Generation” to describe those Americans who had lived through the Great Depression and who had fought in World War II. In his 1998 book of the same name, Brokaw wrote, “it is, I believe, the greatest generation any society has ever produced.” They fought, he wrote, not for fame and recognition, but because it was the “right thing to do.”

I am old enough to have a very direct connection to that generation… in its English variant at least. As a kid, WWII and the challenges that generation overcame, were as real and as much a part of my everyday life as Ilderton Road Primary School, New Cross Speedway and Millwall FC.

My mother, aunts and grandparents survived the Blitz on London, and walking to school, my mates and I passed by the ruins of a several houses destroyed during one of the hundreds of air-raids that city endured. Nobody seemed to think it odd or particularly remarkable that more than a decade later, the blasted and burned shells of family homes were left like decayed teeth among rows of otherwise normal looking, if modest, terraced houses in the street next to ours. For my friends and me, it was just a cool place to explore and play in, a situation that would send Health and Safety inspectors into a coma today.

During WWII, my father spent six years in uniform — much of that time in North Africa fighting the Afrikakorps — but he rarely shared stories. Most of any insight I gained about being “at war” came from an uncle who served on a Flower-class corvette assigned to convoy escort duty in the North Atlantic and Mediterranean.

“Uncle Dave” told me about the way his ship rolled around even in moderate seas, dipping her head with every wave and throwing salt water over everything and anyone on deck. He explained how crowded it was, with every inch of space below deck occupied with men or supplies… or both. He spoke about the constant and unappetizing diet of canned and powdered food, and the antics to find anything resembling real food whenever the ship reached harbor. He told me about standing watch on Arctic convoys dressed in every scrap of available clothing, but still feeling the bite of freezing temperatures. The day-to-day routine sounded relentlessly boring, and only occasionally punctuated by any action approaching the classic fight between the Royal Navy and the Kriegsmarine that we see in war movies.

There was no drama about these very occasional “adventures.” He had no flamboyant tales of dashing into action against U-boat wolf packs, and sinking them all. Perhaps this is hardly surprising since the approximately 200 “Flowers” that saw action in the British and Allied navies from 1939 to 1945, are credited with sinking only 47 German and four Italian submarines. His take on the Battle of the North Atlantic was far from romantic. “We lobbed depth charges into the sea that’s about the truth of it,” he said. His take on battle tactics was very simple. “The Old Man [the captain] would steam around hoping to keep the U-boats busy while the convoy disappeared over the horizon. No fuss, just like a drill.”

He spoke about no surface battles with marauding waves of planes trying to bomb the merchant vessels his ship was charged with protecting. No hand-to-hand fighting with crack troops from the Waffen-SS.
In truth, just the good-natured recollections of a young cockney lad from Southwark trying to do what he believed was expected of him… and hoping to make it home at the end of it.

Perhaps because of these stories, both their content and the way they were told to me, I have a true love of ALL shipwrecks that are casualties of war, and especially those who met their end as a casualty of WWII.

And over the years, I have been lucky enough to dive on scores of them, from the Bell Island Wrecks sunk in Conception Bay, Newfoundland, to the Japanese merchant vessels cloaked in living color at the bottom of Truk Lagoon, Micronesia. And in between, wrecks of Nazi and Allied shipping off the coasts of England, France, Nova Scotia, Scotland, the Carolinas, New York and New Jersey. Each wreck, war ship or merchant ship, a story to tell and I am simply glad that through some serendipity, I have the ability to listen.

I did not have the privilege to serve. My father convinced me that a spell in Her Majesty’s Armed Forces was not the best career path for me. Therefore, I have no special context, no special knowledge about how to organize the things these wrecks tell me.

I have simply marvelled at the destructive force of a torpedo while hanging in the water looking at the evidence of one exploding against a steel hull. A hole big enough to drive a London Bus through. The metal melted and twisted, the keel broken by shockwaves, any poor soul standing close by vaporized in an instant.

I’ve swum though holds filled with the materials of war: planes, trucks, explosives, ammunition, uniforms, food, a perfectly intact Sherman tank. All fascinating, all hugely interesting, and something divers like you and me have a special opportunity to visit.

During a trip “home” several years ago to spend time with family, my uncle asked me about the wreck of a U-boat I had recently been on. He wanted to know what class it was, the state of the hull, how it had been sunk, and the usual question about how deep it was.

After a barrage of questions, he finally asked if there were any members of her crew on board. There were and I told him so. He sat quietly for a few moments and then got up to make us a cup of tea. I was left wondering if the tears in his eyes were for buddies on his side of the conflict or for those German sailors who were trying to do what was expected of them… but who did not make it home at the end of it.

TDI Instructor Trainer: Steve LewisSteve Lewis is an active technical diver, instructor/trainer, expedition leader, and a long-time member of TDI. He currently works in the dive industry as a marketing and product consultant for clients in the public and private sectors. He is a successful author and is currently working on a new book about the history of cave diving entitled: Contributions.


The Sinking and First Dive of The Hailey Glasrud Reef

An Interview with Peter Friedman:
Hailey Glasrud sinking

Martin County Artificial Reef Fund was set up several years ago to enhance the artificial reef program of Martin County. Their most recent deployment was the Hailey Glasrud, April 24, 2014, Stuart, FL. She sits in a perfect upright position in 186′ of water. The very uppermost spot is the main upper structure above the bridge at 103′ deep, and the deck level is 164′ deep. Peter Friedman, owner/operator of Stuart Scuba was willing to offer some background information and insight regarding the event, and we have exclusive video from TDI’s own Jon Kieren of the first dive, just minutes after the Hailey Glasrud hit the ocean floor.

Exact coordinates: 27°12.580 / 80°00.287

TDI. How did this come about and who payed for it?
PF. MCAC Reef Fund ( has been raising funds for such reefs since 2003. This is their 4th ship deployment. The organization acquires the vessels, then transfers the ownership and donates the ship to Martin County for deployment on their permitted reef sites. A major donor is given the rights to name the vessel. In this case it was Ted Glasrud who picked his granddaughters name: Hailey. The project did not really start until we were sure there was enough money to complete it.

TDI. Why do this? How does it benefit the environment, and is that the main reason?
It’s all about creating fish habitat. There are different types of reefs that are created for different reasons. These types of reefs are typically constructed to enhance opportunities for the fishing public. Due to the depth this was sunk, diving should be restricted to those with technical skills and certifications. Other reefs, in shallower water might be created as dive destinations, as others might be constructed to enhance fish populations. The MCAC Reef Fund has three goals: to attract more fish to the area and to improve our aquatic population, to bring more fishermen and divers to our area, and to improve our undersea environment.

TDI. What is the ship’s history? Who owned it, and was it donated or purchased?
This ship was purchased from Miami Dock Operators and Freight Forwarder. Total cost including the deployment, is estimated at approximately $150,000. She has changed hands many times and we have included her history along with pictures and videos of the sinking on the MCAC website.

TDI. How was it sunk? With explosives? What are the logistics involved in having it land right side up?
The hull was flooded by six openings that were cut just above the waterline (three on each side). These openings were plugged during transport to the deployment destination. The openings were cut open, two pumps pumped water to the bilge and 2″ – 6” valves were cut open, allowing more sea water to flow in. Although the ship was listing hard port as it went below the water, air trapped just below the main deck righted the vessel and it landed upright. Also six openings, about 3 sqft., were cut below the water line at very low tide, and plugged until sinking. Six additional holes were cut into the ship well above the water line to make access for fish habitat once on the bottom.

Kurt Francis: First to Hit the deck of Martin County’s Newest Artificial Reef: the 190′ freighter Hailey Glasrud. She sits at 186′ in the sand, smoke stack is at 103′. Nice dive and looking forward to the next time after the silt settles. Vis was very limited inside the wreck, at about 30′-50′ (kept changing). Mild current at the start of the dive and increasing by the end of the dive. Thanks to Stuart Scuba and the crew for a Great drop (right on the orange platform!) Also, thanks to Jon Kieren for the video and diving buddy.

TDI. Who was in charge of the event?
Martin County had taken ownership of the vessel at the deployment site, and was responsible for safe and accurate operations. The MCAC was responsible for the ship until the sinking. This project was overseen by the MCAC’s President, John Burke. He conducted the negotiations with the tug boat operator as well as the past owner of the vessel. Once the vessel was sunk, ownership was transferred to Martin County by agreement and legal documents. This has also been the case with other vessels that MCAC has added to the Martin County artificial reef.

TDI. Who decided on the location, and why?
The site is the Sirotkin Reef site which is permitted by Martin County. Since the vessel was purchased and donated by the MCAC, the county worked with the MCAC to identify a location that was acceptable to both. This long standing partnership between the MCAC Reef Fund and Martin County has produced a number of successful deployments.

TDI. After the ship sunk – what happened next?
A post deployment dive occurred within an hour of the deployment by TDI Certified technical divers. Also, cameras strapped in various locations on the deck documented the real time sinking experience. These videos are available to watch at There were also about 30 boats on site watching the deployment.

TDI. What happens now? Is the site open to all divers? What will happen to it over time?
It is a technical dive and should only be done by skilled divers. This particular wreck was not constructed as a sport diving destination. The focus of reefs constructed at these depths is for fishing and bringing more fish into the area. This wreck was sunk in an area that has had other deployments in the past, and these also have become sites for technical diving. Other artificial reefs have been deployed that are in the sport diving range, and can be located at The ship will age over time, however there are vessels off the Martin County coast that were deployed over 30 years ago, and they remain in structurally sound condition. Thick walled, steel vessels like this one should have an extended lifetime at this depth.

Many thanks to Peter Friedman, Kurt Francis, and the rest of the crew at Stuart Scuba –


Have You Dived the Empress of Ireland: Canada’s Titanic?

The Maritime Museum of British Columbia is looking for film footage and photos of the Empress of Ireland

Empress of Ireland

photo credit: Maritime Museum of BC

The Maritime Museum of British Columbia is proud to be opening a temporary exhibit commemorating Canada’s most infamous maritime disaster: the sinking of the Empress of Ireland on May 29, 1914.

The 100th anniversary of this tragedy is on May 29, 2014, the same day as the official opening of the exhibition, which will have a soft opening on April 29th and run until October of 2014. In support of the exhibit, the Museum is hosting a small panel discussion and presentation by divers who have experienced the wreck firsthand, which will focus on the excitement and risk of diving this challenging site. The story of the Empress did not end with her sinking and the loss of over 1000 lives, but continues to this day as an evolving historic dive site.

To aid this presentation, the Museum is seeking any photographs or film footage of the Empress in her final resting place that the diving community may have. Digital copies are preferred wherever possible, but hard formats will be gratefully received.

Dan Downes of TDI is our point of contact for the panel, so if anyone has such footage and is willing to share it, please contact him at or contact TDISDI Headquarters.

Any such footage would be fully credited back to the owner if they so desired.

We are excited and honored to have the opportunity to enhance the public’s knowledge and understanding of this largely hidden Canadian National Historic Site.


Grain at the Bottom of the Sea

by Cristiana Rollino and Maids Wallace (SDI/TDI Instructor 5280)

Sardinian wreck 1

Photos by Attilio Eusebio (SDI/TDI – Instructor Trainer 10319)

Many thanks to Maids, a beginner in scuba diving, who has not only managed to translate this account in to English, but who has also understood my struggle in the world of technical diving.

Attilio used to tell his friends: “She’s not interested in fish… she likes shipwrecks!” I was branded a tomboy.

Sardinian wreck 2
I sincerely do like shipwrecks because they epitomize nature’s quiet but unrelenting take over of everything that contaminates it. They lie on the seafloor, oblivious to the dramatic event which has sunk them. They are sometimes a tangible confirmation of a real war or an other-world image in a documentary, their shape deformed by fire, by the explosion of a bomb or a torpedo. They are colonized by marine life which is unaware of the history of its dwelling place. My curiosity about shipwrecks, many of which lie below the 40 meter mark, led me to attend a “Decompression” course and subsequently “Normoxic Trimix”, both held by TDI. So, this is also the story of my wary approach to technical diving.


Sardinian wreck 3The simplest part was using bail-out tanks. Bi-tanks (10 + 10 liters), however, posed a more serious problem. Despite modifying the equipment configuration many times, I kept descending head first: even though I kept counterbalancing with fins and back muscles, I used to get out of breath and sometimes had narcosis symptoms. At last, a sympathetic soul on a diving forum suggested I shorten the crotch of my inflatable jacket and add a tail weight, thus eliminating my trim problem.

The Mediterranean basin was frequently a theatre for battles between the Italian Regia Marina (Navy) and the British Royal Navy during the Second World War.

Wrecks from that period can be found in the seas south of Sardinia and divers from all over Europe go there to investigate.

Many of them, like us, go to “Pro Dive Diving Center”, run by Susanna Sabbioni (SDI Nitrox Instructor) and Stefano Bianchelli (SDI/TDI Instructor Trainer, specializing in rebreather training), which can supply gases for tanks and a competent guide. That’s Stefano himself, who knows the area very well and whose technical ability is widely recognized. He’s got a bit of a crafty look but he’s really very helpful and good natured.

Sardinian wreck 4The dive center is situated in Villasimius, a small village renowned for its marvelous sandy beaches: Simius Beach and the adjacent Giunco Beach , where the salt marsh lagoon hosts colonies of pink flamingoes.

The Loredan (-54/65 m) and the Isonzo (-43/57 m) (Fig. 1 and 2), which were part of a convoy torpedoed on 10th April 1943 by a British submarine, were our first diving destinations. The most curious wreck, however, was, in my opinion, the armed cargo ship Salpi. It was torpedoed by a British submarine on 9th February 1942 in the waters around Cape Ferrato and lies at around -47 to 60 meters depth. We planned our dive for 22 minutes at 58 meters with Trimix 18/40 and decompression with EAN50 and EAN99.

We descended along the rope, which reaches the central part of the ship. A big cannon was sitting on the stern (Fig. 3) and it was possible to get into the various holds (Fig. 4). There was a well preserved explosives magazine in one of these and it was possible to make out the lines of bullets laid out tidily (Fig. 5), ready for use. Two big anchors were visible just in front of the magazine.

Sardinian wreck 5The most extraordinary thing was, however, the load of loose grain, which filled one of the holds. It was at least one meter high! (Fig. 6). It was just like grain one could buy at the market; one could sink one’s hands into it. It was covered with a 20 cm jelly-like layer, floating over the grain like a cloud; perhaps it was secreted by the grain itself.

Why hadn’t the grain been eaten by fish? Perhaps there aren’t omnivore fish at that depth, or perhaps metabolic fermentation processes are drastically slowed down. Unfortunately, a scientific explanation was not forthcoming, even though I asked marine biologists.

In another hold, a 4 cm layer of paraffin was floating near the ceiling. It had probably been used to make light. Stefano claimed that it was perfect for lubricating the zips on our diving suits…an inglorious end for a historic relic.

I was enthusiastic about this dive (Fig. 7), but it’s well known that our emotions are but fleeting moments, memories recorded in our brain so that they can fill our future.

Sardinian wreck 6


Fig. 1: The Isonzo cannon
Fig. 2. The Isonzo cannon
Fig. 3. The Salpi cannon
Fig. 4. Wheeled carriages
Fig. 5. Charges
Fig. 6. The grain in one of the holds
Fig. 7. Going back up to the rope


Wreck Diving Solves Archaeological Mystery

by Tamara Thomsen:

2 wreck divers

Photo Credit: Tamara Thomsen

On November 2, 1905 the goliath, wooden steamer Appomattox attempted to navigate into the harbor at Milwaukee’s North Point through fog and smoke so dense that the ship was enveloped in darkness. For nearly two weeks efforts were made to release the steamer, but she was eventually abandoned and broke up. Her machinery was subsequently salvaged, and today she lies in 20 feet of water only 150 yards off Atwater Beach just north of Milwaukee, Wisconsin, her hull broken and scattered across the sandy bottom.

To many divers, a broken hull like that of the Appomattox holds less appeal compared to more intact vessels – even ships that are entirely stripped of rigging, gear, and artifacts. But to an underwater archaeologist or any diver with an analytical eye, these sites present a prime opportunity to study and learn about wooden vessel construction. The advantage of broken hulls like the Appomattox’s is they offer a view of many construction details that are hidden in more intact vessels. Like a fingerprint in a forensic investigation, construction features identified in the scattered remains can offer means of identifying a shipbuilder.

The Appomattox was launched in 1896 by master shipbuilder James Davidson, and was the world’s largest wooden bulk steamer ever built. Davidson’s career straddled the transformation from wooden to steel hull construction on the Great Lakes, but Davidson continued to push the engineering window to extend length limits of wooden ship construction at a time when many of his contemporaries switched to building with iron and steel. He utilized wide steel arches to strengthen his hulls (called hogging trusses), which ran the length of his hulls longitudinally. Internally in his hulls, Davidson utilized a lattice-like iron basket frame attached to the vessels structural frames. This prevented the wooden planking from separating and opening up due to the burden of stress and work in waves, and under cargo weight.

In 2003, archaeologists from Wisconsin Historical Society’s Maritime Preservation and Archaeology Program along with many local volunteer divers endeavored to piece together the history of the Appomattox. Like virtually assembling an expansive puzzle on the bottom of Lake Michigan, nearly all pieces of her 319-foot hull were located and documented in the survey. However, one gargantuan piece of the vessel was missing – the entire length of the starboard side of the ship. When I visited the Appomattox to photograph the wreck, I heard stories of another local wreck previously identified in the early 1980’s by local divers as the steamer Josephine. It was located just inshore, so we plunged into the cool waters of Lake Michigan once again to survey this vessel.

By examining the dimensions and spacing of diagnostic timbers on the Josephine, and the absence of a keel, it was determined that the “Josephine” was in fact the missing starboard section from the Appomattox shipwreck! Our careful observations led to the conclusion that this was not a separate shipwreck as was previously thought. Not only were the two ships united as one, but archaeological clues found in the “Josephine” wreckage allowed us to discover an important missing characteristic to Davidson’s vessel construction.

The presence of both interior and exterior steel arches spanning the entire length of the vessel’s sides provided evidence for Davidson’s use of hull-strengthening techniques. After this discovery on the so-called Josephine, reinvestigation of the main wreckage site yielded previously undiscovered remnants of an interior hogging truss. This is the first time this construction technique has been archaeologically recorded for one of Davidson’s vessels.

Much of what we know of Davidson’s work we have learned from the archaeological record, which exists on the lakebed today. The discovery that two shipwrecks were actually fragments of the same ship combined with careful surveys of the wreck at both locations provided important historical evidence for Davidson’s reinforced hull construction. As a result of this work, the Appomattox wreck site has been listed on the National Register of Historic Places.

Tamara ThomsenTamara Thomsen is a Maritime Archaeologist with Wisconsin Historical Society’s Maritime Preservation and Archaeology program. Her research has resulted in thirty-eight Great Lakes shipwrecks added to the National Register of Historic Places. She has participated as a photographer, researcher, and research diver on projects ranging from the USS Monitor with NOAA National Marine Sanctuaries to RMS Titanic with Woods Hole Oceanographic Institution. She has been an active TDI Instructor since 1996 and is a 2014 inductee into the Women Diver’s Hall of Fame.


Wreck Diving: You can dive around it, learn to dive in it!


Photo by Bill Downey

Is it the mystery, the beauty, the history, or the adventure that first drew your attention to wreck diving?  No matter what your personal appeal, almost everyone who has looked through a doorway or porthole of a shipwreck has wanted to venture inside and unlock the real mystery.

While this can be hazardous to the untrained, those hazards can be reduced and it can be an exciting, and rewarding adventure for those who have taken the extra training to dive it correctly.  The SDI Wreck Diver course will provide you with the skills necessary to dive through swim throughs or within the ambient light zone of the entry point of a wreck safely.

While diving inside a shipwreck can be fun and exciting, it can also be hazardous if the necessary precautions are not taken.  The inside of a wreck can seem well lit and inviting when you are looking from the outside in, especially in the ambient light zone.  However, there are many issues that many do not consider before venturing inside.  Entanglement hazards and the silt that may have been accumulating undistributed for years can cause serious problems for the unprepared diver.

The SDI Wreck Limited Penetration Diver course will teach you how to manage these hazards; you will learn how to:

  • properly plan a limited penetration dive
  • avoid and manage a silt-out inside the wreck
  • deploy and follow a guide line
  • properly use dive lights
  • how to map the wreck noting potential hazards for future dives.

These skills are essential tools for a penetration dive, no matter how benign it may seem when looking at it from the outside.

Whether you are trying to unlock the mystery of a long lost ship or just enjoy the beauty and marine life associated with wreck diving, attending an SDI Wreck Limited Penetration Diver course will provide you with valuable tools to enhance your wreck diving experiences.  For more information on SDI Wreck Diving visit or your nearest SDI Dive Center or click here to learn more!

Contact SDI TDI and ERDI
If you would like more information, please contact our World Headquarters or your Regional Office.

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