Sinking ships for wreck diving sites is the practice of

scuttling Scuttling is the deliberate sinking of a ship. Scuttling may be performed to dispose of an abandoned, old, or captured vessel; to prevent the vessel from becoming a navigation hazard; as an act of self destruct, self-destruction to prevent the s ...

old

ship A ship is a large watercraft that travels the world's oceans and other sufficiently deep waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research, and fishing. Ships are generally distinguished ...

s to produce

artificial reef An artificial reef is a human-created underwater structure, typically built to promote marine life in areas with a generally featureless bottom, to control erosion, block ship passage, block the use of trawling nets, or improve surfing. Many re ...

s suitable for

wreck diving Wreck diving is recreational diving where the wreckage of ships, aircraft and other artificial structures are explored. Although most wreck dive sites are at shipwrecks, there is an increasing trend to scuttle retired ships to create artificia ...

, to benefit from commercial revenues from

recreational diving Recreational diving or sport diving is diving for the purpose of leisure and enjoyment, usually when using scuba equipment. The term "recreational diving" may also be used in contradistinction to "technical diving", a more demanding aspect of r ...

of the

shipwreck A shipwreck is the wreckage of a ship that is located either beached on land or sunken to the bottom of a body of water. Shipwrecking may be intentional or unintentional. Angela Croome reported in January 1999 that there were approximately ...

, or to produce a

diver training Diver training is the set of processes through which a person learns the necessary and desirable skills to safely dive underwater within the scope of the diver training standard relevant to the specific training programme. Most diver training ...

site. To avoid undesirable

ecological impact Environmental issues are effects of human activity on the biophysical environment, most often of which are harmful effects that cause environmental degradation. Environmental protection is the practice of protecting the natural environment on t ...

, and to maximise utility, the vessel should be selected and prepared, and the site chosen, with due consideration to the local environment.

Preparation

To prepare a

hulk The Hulk is a superhero appearing in American comic books published by Marvel Comics. Created by writer Stan Lee and artist Jack Kirby, the character first appeared in the debut issue of ''The Incredible Hulk (comic book), The Incredible Hulk' ...

for sinking as a wreck site, several things must be done to make it safe for the marine environment and divers. To protect the environment, the ship is purged of all oils,

hydraulic fluid A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backhoe ...

s, and dangerous chemicals such as

PCB PCB may refer to: Science and technology * Polychlorinated biphenyl, an organic chlorine compound, now recognized as an environmental toxin and classified as a persistent organic pollutant * Printed circuit board, a board used in electronics * ...

s. Much of the

superstructure A superstructure is an upward extension of an existing structure above a baseline. This term is applied to various kinds of physical structures such as buildings, bridges, or ships. Aboard ships and large boats On water craft, the superstruct ...

may be removed to prevent the hazard of it eventually caving in from

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

. Similarly, the interior of the ship is gutted of components that corrode quickly, and would be dangerous to divers if they came loose. The ship is thoroughly cleaned, often with the help of volunteers interested in diving. A significant part of the cost of preparing and sinking the ship may be recovered from scrapping the contents of the ship, including valuable materials such as

copper Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...

wiring. The hulk's suitability as a diving site may be enhanced by cutting openings in its hull and interior bulkheads, and removing doors and hatch covers to allow divers access at reduced risk.

Choice of site

Several factors influence the choice of site for recreational diving purposes, and these should take into consideration the possibly conflicting economic and ecological considerations. * The wreck should not create a significant hazard to navigation. * For maximum accessibility and diver safety, a shallow site in protected waters is preferred. ** To reduce cost of access, the site should be near to a suitable harbour or launching site, in a region where existing or planned recreational diving infrastructure is available. ** There may be a conflict of interests between groups which may profit from access to the wreck. * Sites further offshore make shore dives impracticable or dangerous. * Deeper water reduces access to less qualified divers, but increases risk for all divers. * More protected waters reduce risk to all divers and increase the useful lifespan of the wreck as a diving attraction. * Placement of the wreck will do some ecological damage. An ecological impact assessment should indicate acceptable long term consequences. * The site will influence the marine organisms that will colonise the wreckage, and the rate at which they will grow. Some may be more desirable at a dive site than others. * The site will influence the rate of silt deposition in and on the wreckage, which will affect safety and the local ecology.

Sinking

The preparation phase usually removes a significant amount of weight, so the ship floats higher in the water than normal. This may make it necessary to stabilise the vessel by filling some compartments with water as makeshift

ballast tank A ballast tank is a compartment within a boat, ship or other floating structure that holds water, which is used as ballast to provide hydrostatic stability for a vessel, to reduce or control buoyancy, as in a submarine, to correct trim or list, ...

s to prevent excessive

rolling Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact ...

in port or during

towing Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, and the load being anything that can be pulled. Th ...

. The ship is towed to the sinking location, usually in waters shallow enough to allow access by numerous divers, but deep enough to be relatively unaffected by surface weather conditions. The ship is usually scuttled using shaped explosives, in a controlled demolition. The holes may be blown so that the heavier engine room and stern floods first, then the rest of the hull. The aim is to sink the ship in an upright position.

Reception

The sinking of ships as recreational dive sites can provide wreck diving opportunities where they previously did not exist, and can provide wrecks which are particularly suitable for penetration by less skilled and experienced divers, when they have been prepared for the purpose by removing potential hazards and contents which would contaminate the site or region. However, some divers see them as artificial, less interesting and less challenging, and prefer to explore the relatively unknown or mysterious surroundings of historic and significant wrecks which occurred outside planned scuttling events, considering them to be more authentic. Scuttling programs may relieve more culturally significant wreckage from overexploitation, particularly incidental damage by less competent divers, but do not remove the threat of illegal intentional damage by removal of artifacts by wreck-robbers, who will target wrecks where there are more likely to be artifacts worth stealing.

List of ships sunk for wreck diving

References