Where I live it is quite normal that if you are an adventurous sportsdiver that you go wreckdiving at the Northsea.
And with the boat I go, people are used to penetrate the wrecks. 1 rule that is told to every diver: take a reel. The wrecks are not so big here. The skipper tells sportsdivers about the hazards of wreckdiving: currents (tidal), sharp parts, unstable parts, etc. The depth is maximum 30m, 90ft. Dive nitrox and stay withing NDL.
You can do a Northsea wreckdiver course here. But the quality depends on the instructor.
From this wreckdiving I went into cavediving as my interests where more than sportsdiving. Now I learned to use a reel, etc (I used a reel before, but did not know about tie offs, so I used it, but not properly). And with this knowledge I changed my wreckdiving. I now do with my cavediving cert and the knowledge of the hazards of wreckdiving told by the skipper my wreckpenetrations to all depths that I want to do.
A good cavern or wreckdiver course will help. But the full cave divers have a lot of advantages. The distances to open water are shorter in wrecks than in caves. Entanglement risks in caves are different from wrecks (cables, steel, sharp edges in wrecks), but you get the same risks in mines. Even unstable parts in wrecks and mines are found.
Here a picture of diving a blast furnace, see the risk of entanglement. And risk of siltout, perculation, etc. It is an overhead environment, no tidals, no currents, no waves, but the rest is more or less the same as in wrecks:
Here another risk of a mine, the wooden parts can be rotten. Bubbles can make it instable (rotting process changes by oxygen/air vs only in water, sometimes wood already rotten before it was flooded because of moisture when mine was in use). The walls can instable as well.
The full cavediver that goes cavediving or minediving has already the techniques, the diver need to recognise the new risks in more instable environments (sharp edges, entanglements, etc). I learned this from a skipper and by reading and going with experienced wreckdivers. The cave course was most usefull for the techniques I needed. When you are no cavediver and want to dive wrecks, I would say do a wreckdiver course or a caverncourse. If you are a full cavediver, know the differences and build up experience slowly. You know the techniques.
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