WIT Concrete Wreck

The WIT Concrete Wreck is one of St. Thomas's most unusual and unexpectedly rewarding dive sites — a vessel constructed from concrete, a material used in a brief but fascinating period of marine engineering when steel shortages made alternative construction methods attractive, now resting on the seafloor as an artificial reef with a biological community uniquely shaped by the chemistry and texture of its concrete hull. The WIT designation refers to Water Island, a small island off the St. Thomas waterfront, in whose vicinity this and other wrecks have been documented. Concrete vessels were built in significant numbers during the First and Second World Wars when steel was prioritised for weapons manufacture, and their unusual hull material gives them a distinct character as dive sites. The concrete, while not as biologically attractive as steel to many encrusting organisms, provides excellent attachment surfaces for different community types — particularly the coralline algae and certain sponge species that colonise rough mineral surfaces effectively. The result over decades of immersion is a wreck that looks quite different from steel-hulled vessels, with different biological patterns and in some ways a more natural integration into the reef environment. The marine life around the WIT Concrete Wreck is nonetheless excellent. The vessel's structural complexity provides the shelter and attachment surfaces that reef fish require, and the community that has established here includes all the fish and invertebrate species characteristic of the Virgin Islands artificial reef environment. Grouper have claimed specific compartments, schools of snapper orbit the main hull, and the moray eels that are ubiquitous on Virgin Islands wrecks occupy every accessible crevice. For intermediate divers interested in the unusual aspects of wreck diving — the historical engineering context of concrete hull construction, the different biological succession that concrete substrates support, and the challenge of navigating a wreck whose layout may be less familiar than conventional steel vessels — the WIT Concrete Wreck provides an intellectually engaging dive experience alongside the standard wreck diving pleasures of marine life discovery and structural exploration.