Wreck diving in 2000: Tech and protection

Ships as reefs and as overhead environments — from the Yongala and Thistlegorm exteriors to cavern-style penetration risk. Wreck diving is scuba on a ship, aircraft or other structure. The recreational default is an exterior circuit: look, do not enter. Penetration — swimming under a deck with no direct ascent — is an overhead environment and sits at the high-risk end of this atlas.

Famous wrecks (SS Yongala, 1911; SS Thistlegorm, 1941; Coron’s 1944 fleet) are also artificial reefs and war graves. Parks and navies write rules that a specialty card does not override. This chapter is not a penetration briefing, not a salvage licence, and not medical advice. Silt-outs and line reels belong to a living instructor in a controlled site.

Agency cards (PADI/SSI/federations) gate depth and gas — not Instagram. Local shops own currents, checkouts and boat briefings. Medical forms and insurance differ by country; renew before the trip. Wreck diving mapped for mechanisms, locale notes and limits. Wreck diving sits in the scuba atlas — mechanisms, locale notes and limits, not slogans.