GUE vs UTD vs Hogarthian: How the DIR Family Tree Differs

Disclosure: Gardner Underwater teaches through UTD, and Jay Gardner was an owner of UTD until 2026. We've tried to describe both agencies fairly and link to their own descriptions so you can check.

The terms get used interchangeably online, which causes a lot of confusion. Here's how they fit together.

The short version

What is the Hogarthian configuration?

The Hogarthian configuration is a minimalist way of setting up scuba gear: backplate and wing, a continuous-webbing harness, a long-hose primary regulator, a backup on a necklace and as few extra items as possible. It's named for cave diver William Hogarth Main; Jarrod Jablonski's account of the history describes the divergence between the Hogarthian gear concept and wider DIR system.

Hogarthian is only about equipment. Many agencies' technical programs teach Hogarthian-style rigs without teaching the wider DIR system. For the pieces and the reasons behind them, see DIR Gear Configuration, Piece by Piece.

What is DIR?

DIR, "Doing It Right," takes the Hogarthian configuration and builds a complete system around it: fundamental skills, team diving, standardized gases and procedures, gas planning and fitness. It developed through cave-diving exploration and team standardization within Florida's Woodville Karst Plain Project, notably involving divers such as George Irvine and Jarrod Jablonski. See Jablonski's history of DIR and GUE. We explain it fully in What Is DIR Diving?

DIR itself isn't an agency and doesn't issue certifications. Agencies do.

What is GUE?

Global Underwater Explorers is a training agency built on the DIR system. Its entry point is now split into two courses, according to GUE's Basic Fundamentals page and its Technical Fundamentals page:

• Basic Fundamentals normally runs three days, with at least six dives and 24 hours of in-person instruction, to a maximum of 60 feet. It covers configuration, trim, buoyancy, propulsion including the backward kick, valve management, gas sharing, SMB deployment and nitrox, in a single cylinder or doubles.
• Technical Fundamentals normally runs four days, with at least eight dives and 32 hours of in-person instruction, to a maximum of 100 feet. It's the gateway into GUE's technical and cave training, and it asks for 75 logged dives and doubles experience first.

For a side-by-side look at both agencies' entry courses, see UTD Essentials vs GUE Fundamentals.

What is UTD?

Unified Team Diving is a training agency that grew from the same Hogarthian and DIR roots. In 2008 it set a new direction: unifying backmount, sidemount and rebreather diving into one consistent, scalable and interchangeable system (UTD).

UTD describes itself as an inclusive philosophy, and its ideal is a "thinking diver" rather than a "protocol diver": someone who understands why each practice exists, not just how to perform it. UTD courses can be taken in backmount or sidemount, singles or doubles, as each course allows. At Gardner Underwater, the UTD path for certified divers looks like this:

1. Essentials of Recreational Diving: the entry point into the UTD system for certified divers, normally over three days with video debriefs.
2. Essentials of Tech: a no-decompression personal skills class that prepares you for technical diving.
3. Techreational and Tech 1: limited decompression diving on standard gases, to 130 feet and then 160 feet.

How do GUE and UTD differ?

They share far more than they don't: the same core configuration, a team focus, gas planning, standardized procedures and an emphasis on fundamental skills. The differences are mostly about scope and structure.

• Sidemount and rebreathers. UTD's stated aim is one consistent system across backmount, sidemount and rebreathers, so a team can mix platforms and still share the same protocols.
• Entry structure. Both agencies now split their entry point in two: GUE into Basic and Technical Fundamentals, UTD into Essentials of Recreational Diving and Essentials of Tech.
• Course names and progressions. Each agency has its own sequence and standards, which change over time. Always check the agency's current course pages.

Which should you choose?

The instructor matters more than the logo. Look for these things before you look at the agency:

• Do they dive the way they teach? Ask to see video of their own diving.
• Do they explain the why? Good instructors welcome questions about the reasons behind each practice.
• Is the training near where you'll dive? Logistics decide a lot. A great instructor you can train with regularly beats a famous one you see once.
• Where do you want to go? If sidemount or rebreathers are in your future, ask how each agency's system handles them.
• Will they tell you when you're not ready? Honest feedback is the most valuable thing you're paying for.

Strong fundamentals carry over either way. If you're switching agencies, the instructor will assess where you are and what you still need.