Meet the NAUI International Technical Diving Summit Leadership and Staff Teams
The NAUI International Technical Diving Summit (NITDS) is just around the corner!
Join us October 31 – November 8, 2025, in the heart of Florida’s Cave Country for an unforgettable week of advanced diving education and exploration.
NAUI is proud to introduce a highly experienced leadership team and support staff dedicated to delivering an exceptional summit experience. Attendees will have the opportunity to participate in expert-led seminars, earn technical diving certifications, and dive some of the world’s most renowned cave systems—all in one comprehensive event.
Don’t miss your chance to advance your skills and connect with the global technical diving community. To reserve your spot or to learn more, visit: https://fareharbor.com/
Leadership Team
David Caldwell - NAUI #42994
David has had a lifelong career in the scuba industry, beginning working at a dive store while in high school. In 1987, he became an open water scuba instructor where his passion led him to Grenada West Indies leading dives to the noted shipwreck, Bianca C. Returning from the Grenada, he became the co-owner and president of the dive store where he first learned how to dive.
Following his tenure being a dive store owner, David co-founded Northern Atlantic Dive Expeditions, Inc. NADE focuses on shipwreck diving, exploration, technical diving training and leadership development. Along with being the co-owner he is a co-captain of the dive charter boat Gauntlet and is the northeastern U.S. and eastern Canada’s regional manager for NAUI Worldwide.
David continues to follow his passions of cave and mine diving throughout the U.S. and Europe, he has had the privilege to dive some of the worlds notable shipwrecks off the eastern seaboard of the U.S., Canada, South Pacific, Red Sea, South China Sea, and the Mediterranean Sea. In addition, he has co-led shipwreck discoveries in his local waters, including the USS Nezinscot, Allentown, among many others, and has collaborated on research projects with NOAA in support of exploration in Stellwagen Bank National Marine Sanctuary.
Through his position with NAUI Worldwide, David is a Course Director Trainer and Technical Examiner, he is a fellow member of the Explorers Club, associate member of the Boston Sea Rovers. David is also employed as an Assistant Harbormaster for the City of Beverly Massachusetts and is a member of the board of directors for Salem Sound Coast Watch. Parallel to having a career in the dive industry, he’s had an industry career in global product management and application engineering.
Heison Chak - NAUI #59648
Heison Chak is a Recreational, Technical, and CCR instructor with over a decade of experience in teaching and mentoring divers. His unwavering commitment to dive safety is exemplified by his extensive contributions to the Ontario Underwater Council (OUC) since 2015, where he served as Director of Sport Safety before being elected President.
As a NAUI Course Director and Technical Instructor Examiner, Heison works closely with NAUI HQ to shape the next generation of diving leaders. Through his involvement in Leadership Conferences and the NAUI Mobile Training Team, he focuses on cultivating the skills and leadership qualities of aspiring divers, fostering a culture of safety, excellence, and innovation within the diving community.
Timmy Young - NAUI #53589
Timmy brings over 30 years of dive experience and instruction to every course, having started diving in 1985 and teaching by 1990. As a NAUI Cave Instructor and Instructor Evaluator, he trains divers at all levels, including those pursuing professional certification. Timmy’s depth of knowledge spans both recreational and technical diving. His approach supports NAUI’s mission of safety through education, developing well-rounded, responsible divers capable of exploring diverse underwater environments. From skill-building to cave exploration, Timmy provides a training experience rooted in excellence, integrity, and respect for the underwater world.
Daniel Millikovsky - NAUI #30750L
Daniel Millikovsky, originally from Argentina, has been a diver since 1993 and a NAUI Member and Instructor since 1998. In 1999, he became an Instructor Trainer, and by 2000, he was appointed as the first NAUI Course Director in Argentina.
That same year, he relocated to Cozumel, Mexico, where he served as Training Director for the Hyperbaric Chamber Clinic at Buceo Médico Mexicano SSS and also worked as local staff for the DAN PDE program in Cozumel. From 2001 to 2005, he operated his own dive center on the island before returning to Argentina to establish Argentina Diving.
In 2013, he became a NAUI CCR Extreme Exposure Mixed Gas Instructor Examiner for the Hollis Prism 2 unit. He received the NAUI Outstanding Service Award in 2015 and was appointed NAUI Representative for Argentina in 2016. Since 2023, he serves as the NAUI Southern South America Regional Manager.
For over 15 years, Daniel has co-owned Argentina Diving with his wife—a NAUI Pro Platinum Dive Center (#1526), recognized as a Professional Career Training Center and a Technical Diver Training Center. The company also distributes premium diving equipment from top manufacturers in the USA, Canada, and Italy.
Terrence Tysall - NAUI #16627
With 44 years of diving experience, Terrence N. Tysall SR. is one of the underwater world’s most accomplished explorers. From deep WWII wrecks of the South Pacific, to the submerged caves of Yucatan, Belize, and Bermuda, to the historic wreck of USS Monitor, to the lava tubes of the Canary Islands, Terrence has dived some of the planet’s most remote waters gathering data about what lies at the bottom and beyond.
Terrence has led multiple scientific/research expeditions around the world, including the first SCUBA exploratory dives on the SS Edmund Fitzgerald in Lake Superior, the USS Atlanta off of Guadalcanal in the Solomon Islands, and the first cave exploration and geologic sampling conducted at the bottom of the Great Blue Hole of Belize.
As a US Army Captain Tysall returned from Iraq and serving stateside as the Commanding Officer of the U.S. Army’s 627th Heavy Dive Team. Now as a MAJ he is the Commander of the FLARNG Officer’s Candidate School at Camp Blanding Florida. He is the founder and past chairman of the board of the Cambrian Foundation, and he is also the founder and president of Benthic Technologies, Inc., a consulting firm that specializes in underwater applications and technology.
On the civilian side; Terrence is currently the Director of Training for NAUI Worldwide. Terrence has earned instructor trainer ratings from ANDI, DAN, IANTD, NAUI, NSSCDS, NACD, SSI, and TDI. In addition to these certifications, Terrence serves on a variety of technical advisory boards for NOAA and other scientific research agencies both in the United States and abroad.
Chris Brock - NAUI #63740
With nearly 20 years of diving experience, Chris began his teaching career in the lakes of Oklahoma before relocating to Florida. An educator at heart, Chris holds a Bachelor’s and Master’s Degree in Education, taught Chemistry and Physics for over a decade, and coached varsity athletics.
Chris is a Course Director, IT, and Technical Instructor Evaluator for NAUI and serves as the Training Director, Instructor Sponsor, and Instructor Evaluator for the NSS-CDS.
With over 1000 cave dives Chris teaches full time with a primary focus on Cave, Rebreather (Fathom MKIII, Fathom Gemini, Optima, Optima Chest mount) and Trimix training. Chris’s motto is “Excellence is earned” and creating opportunities for divers to achieve and excel is the backbone of every class.
Staff Members
Autumn Breeze Jefferson - NAUI #55417
Autumn is a NAUI Instructor Trainer with over 20 years of cave diving experience and a passion for developing safe, confident divers. She has been teaching scuba since 2004, guiding students from their first breath underwater to advanced technical skills. Her focus aligns with NAUI’s mission to promote safety through education, environmental awareness, and a lifelong love of diving.
Elaine (Lain) Li- NAUI #53383
Diving since 2007, Lain is the co-founder of a NAUI training facility in Hong Kong. Her extensive experience as a NAUI Instructor Trainer equips her with the skills to effectively work with divers from various backgrounds.
Presently, Lain is currently the Safety Director at the Ontario Underwater Council. She is dedicated to ensuring safety of the sport in all aspects. Her dedication to promoting safety highlights the crucial role she plays within the diving community.
Carlos Junquera - NAUI #61026
Carlos Junquera is a NAUI Technical Instructor and a leading figure in diving education in Spain, with over three decades of experience as an educator, mentor, and advocate for diving safety and environmental preservation.
He is a NAUI CDT and Regional Manager for Portugal and Spain, Chair of the NAUI International Advisory Committee, and Chair of the NAUI Technical Training Subcommittee. He also serves as European International Advisor to the NAUI Board of Directors and participates in major industry events on behalf of NAUI, such as the European Underwater Federation meetings.
Carlos is deeply committed to the underwater environment, actively organizing and leading debris clean-up events and educational programs as part of scientific research initiatives. He is the founder of PARAMAX Dive and Rescue School, a reference center for technical and recreational diving training in Spain and serves as the Regional Training Coordinator in Spain for DAN Europe. As a seasoned traveler and Brand Ambassador for Master Liveaboards, Carlos connects with the international diving community, sharing his passion for exploration and conservation at top dive destinations worldwide.
His broad experience includes being an advisor to the Spanish Royal Navy League, a life member of the US Navy League, and a member of both the Historical Diving Society – Spain and the National Speleological Society – Cave Diving Section. Carlos is a certified lifeguard instructor, licensed Emergency Medical Technician, Stop The Bleed instructor, and PHTLS-certified by NAEMT. He is also a certified yacht skipper, technical advisor, stunt diver and safety diver for underwater filming of movies and TV shows.
Carlos’s work is driven by a commitment to rigorous training, diver safety, environmental stewardship, and the advancement of technical diving. Through his leadership, teaching, and outreach, he inspires divers to pursue excellence, protect the underwater world, and honor the heritage of the sport within the NAUI community.
Ken Head – NAUI #57145
Ken began his journey as an Open Water Student under the guidance of a NAUI Technical Instructor. Early in his training, he was introduced to Technical Diving and Rebreather Diving, which ignited his passion for diving. This passion eventually attracted others to join him on his quest to become a high-caliber diver. Ken’s dedication led him to co-create and lead a Technical Dive team that embarked on years of rigorous training and global diving expeditions. His diverse experiences in various environments have only further solidified his reputation as an accomplished Technical Instructor.
