Editing Mary Rose (section)

=== Conservation ===

[[File:Mary Rose, Historic Dockyard, Portsmouth, Hampshire - geograph.org.uk - 720237.jpg|left|thumb|alt=A diagonal section of a wooden ship is lying on its side steel frame at an angle, being sprayed with water from dozens of sprinklers|The ''Mary Rose'' being sprayed with water at the facility in Portsmouth in March 1984. Between December 1984 and July 1985 the steel cradle was gradually rotated to stand with the keel in an almost upright position.{{sfnp|Harrison|2003|p=64}}]]

Preservation of the ''Mary Rose'' and her contents was an essential part of the project from the start. Though many artefacts, especially those that were buried in silt, had been preserved, the long exposure to an underwater environment had rendered most of them sensitive to exposure to air after recovery. Archaeologists and conservators had to work in tandem from the start to prevent deterioration of the artefacts.{{sfnp|Marsden|2003|p=145}} After recovery, finds were placed in so-called passive storage, which would prevent any immediate deterioration before the active conservation which would allow them to be stored in an open-air environment. Passive storage depended on the type of material that the object was made of, and could vary considerably. Smaller objects from the most common material, wood, were sealed in polyethylene bags to preserve moisture. Timbers and other objects that were too large to be wrapped were stored in unsealed water tanks. Growth of fungi and microbes that could degrade wood were controlled by various techniques, including low-temperature storage, chemicals, and in the case of large objects, common [[pond snail]]s that consumed wood-degrading organisms but not the wood itself.{{sfnp|Jones|2003|pp=35–43}}

Other organic materials such as leather, skin and textiles were treated similarly, by keeping them moist in tanks or sealed plastic containers. Bone and ivory was [[desalinization|desalinated]] to prevent damage from salt crystallisation, as were glass, ceramic and stone. Iron, copper and copper alloy objects were kept moist in a [[sodium sesquicarbonate]] solution to prevent oxidisation and reaction with the [[chloride]]s that had penetrated the surface. Alloys of lead and pewter are inherently stable in the atmosphere and generally require no special treatment. Silver and gold were the only materials that required no special passive storage.{{sfnp|Jones|2003|pp=47–49}}

[[File:MaryRose-conservation2.jpg|right|thumb|alt=A diagonal section of a wooden ship seen from the stern while being sprayed with a clear liquid from a built-in sprinkler system; on the remnants of the main deck there is a person in a black, full-body protective plastic suit with a yellow helmet|The hull of the ''Mary Rose'' being sprayed at the facility in Portsmouth while a technician services the system]]

Conserving the hull of the ''Mary Rose'' was the most complicated and expensive task for the project. In 2002 a donation of {{Nowrap|£4.8 million}} from the [[Heritage Lottery Fund]] and equivalent monetary support from the Portsmouth City and Hampshire County Councils was needed to keep the work with conservation on schedule.{{sfnp|Childs|2007|pp=204–205}} During passive conservation, the ship structure could for practical reasons not be completely sealed, so instead it was regularly sprayed with filtered, recycled water that was kept at a temperature of {{convert|2|to|5|C|F}} to keep it from drying out.{{sfnp|Jones|2003|pp=40–41}} Drying waterlogged wood that has been submerged for several centuries without appropriate conservation causes considerable shrinkage (20–50%) and leads to severe warping and cracking as water evaporates from the cellular structure of the wood. The substance [[polyethylene glycol]] (PEG) had been used before on archaeological wood, and was during the 1980s being used to conserve the ''[[Vasa (ship)|Vasa]]''. After almost ten years of small-scale trials on timbers, an active three-phase conservation programme of the hull of the ''Mary Rose'' began in 1994. During the first phase, which lasted from 1994 to 2003, the wood was sprayed with low-molecular-weight PEG to replace the water in the cellular structure of the wood. From 2003 to 2010, a higher-molecular-weight PEG was used to strengthen the mechanical properties of the outer surface layers. The third phase consisted of a controlled air drying ending in 2016.{{sfnp|Jones|2003|pp=67–69}}<ref>{{cite web |website=BBC News |date=19 July 2016 |url=https://www.bbc.co.uk/news/uk-england-hampshire-36802829 |title=Mary Rose warship: Full view revealed after museum revamp}}</ref> Researchers are planning on using magnetic [[nanoparticle]]s to remove iron in the ship's wood to reduce the production of harmful [[sulfuric acid]] that is causing deterioration.<ref>{{cite web |url=https://arstechnica.com/science/2018/08/how-magnetic-nanoparticles-will-help-preserve-a-500-year-old-shipwreck/ |author=Kiona N. Smith |title=Tiny magnets will escort ions out of rare material from a shipwreck |date=24 August 2018 |access-date=25 August 2018 |website=[[Ars Technica]]}}</ref>

The wreck site is legally protected. Under the "Protection of Wrecks Act 1973" (1973 c. 33) any interference with the site requires a licence. The site is listed as being of "historical, archaeological or artistic importance" by [[Historic England]].<ref name="NHLE|num=1000075">{{NHLE|num=1000075|desc=Mary Rose|access-date=4 October 2021}}</ref>