Forensic studies demonstrate that in most marine environments a human corpse will be reduced to skeletal form in less than three weeks, although some degree of articulation may prevail for as long as 18 months. Following the loss of soft tissue, skeletal surfaces are abraded by current-driven sediments. Physical transport of the
remains by currents may result in their impact with hard surfaces to cause additional breakage and dispersal.
Biological activity involving boring, encrusting and scavenging further degrades bones, resulting in advanced deterioration within 12 years, even in cases of the most
durable skeletal parts. As a result, the vast majority of human bones on shipwrecks
are only preserved if and when a victim became trapped below decks, such as beneath cannon and cargo.This prevents dispersion until a sealing layer may be deposited to preserve bone within an anaerobic environment.Therefore, the degree of preservation will depend on how quickly the remains become sediment-inundated and whether such burial seals out oxygen – the main reason that mud and clay are superior to sand for this purpose
Limited skeletal remains typify wrecks located in sandy and hard mud environments, as opposed to fluid mud contexts like the Mary Rose, Kronan and Vasa, where human bones should be expected and are common. The survival of soft tissue only survives in
the most rare of warm or mineral-rich springs and cold,oxygen-depleted environments , such as on the 17th-century La Belle shipwreck in Matagorda Bay, North America.
Quo Fata Vocant-Whither the Fates call