@victorzamora Here's what you need to understand on the combination of decompression / technical training and technical wreck:
Most, if not all, contemporary technical wreck courses were originally drafted using full cave as the template.
However, wrecks tend to be deeper than most cave systems. The diver needs to get down to the wreck and still have ample bottom time to complete a meaningful penetration. This made decompression training a logical prerequisite.
There's lots of caves where students can achieve meaningful training penetrations without incurring deco. There aren't many wrecks that offer the same. Wrecks tend to deteriorate quickly in shallow depths.
Given that technical wreck students should already possess solid proficiency in technical decompression diving, it would be ludicrous to repeat the elements of cave training that deal with technical equipment, long hose, signals, propulsion, trim, buoyancy, communication, use of lights etc etc
To do so would be a completely unnecessary replication. As a consequence, these elements were logically removed from the syllabus - thus shortening it.
Nothing was removed from the syllabus regarding overhead environment penetration skills, drills and procedures.
Some elements are also added, specific to diving wrecks - deploying ascent lines, marine hazards, risk awarenss and mitigation for unique wreck hazards; loose electrical wiring, fishing nets and lines, unstable structures and collapse leading to injury or entrapment.
The environmental theory is, obviously, different. We consider current, surge and tide, rather than flow. We deal with man-made particulates, rather than tanninity etc. We learn about chemical contamination from cargos or fuels, rather than naturally occurring hydrogen sulfide etc. Preserving artifacts, rather than rock formations. Silt issues remain silt issues though...
What I'm saying is that a properly trained technical wreck diver should, upon culmination of all required training, possess a level of overhead environment proficiency comparable to a full cave diver - but suitable and specific for a different nature of overhead environment.
Technical Wreck students don't tend, in my experience, to leap into that training directly after completing OC technical training. They are normally more experienced and accomplished technical divers.
As has already been mentioned, experienced tech divers tend to progress faster in overhead training. They've already long surpassed that 'steep learning curve' that recreational divers experience when they first transition into tech kit, team diving, complex protocols etc.
If a qualified, but less accomplished, tech diver did enroll onto technical wreck training - they would expect a longer course timescale to resolve any performance deficits which may be a liability for the overhead environment.
Personally, I don't tend to conduct more than two training dives per day. Usually long dives 60 to 120 minutes each. Allowing time for theory, dry rehearsals and dive planning, that's already a demanding schedule. Most students don't have the physical and mental stamina to give 100% focus if you cram more in.... they might try, but their performance usually declines sharply. That becomes unproductive training.
Subic Bay, specifically, is a mecca for technical wreck because we have big vessels in shallow water... 20-30m. It's an enclosed, very sheltered bay and that has preserved the wreck structures well against storms, currents etc. We get longer dives with easier logistics, much less cost (no trimix reqd!) and minimal decompression. There's four technical wreck instructors working in Subic currently, and many other technical wreck instructors from around SE Asia visit here sporadically to run their courses.
Running technical wreck classes on deeper wrecks is much less efficient. Bigger deco, more cost and significant limitations on bottom time. The emphasis of the course should be on the penetration, not on the deco that just gets you back to the surface.
