King Henry VIII's warship last longer

The Mary Rose ship built between 1509 and 1511, was a firm favourite of King Henry VIII. She sank accidentally in 1545 and her rediscovery has been celebrated amongst nautical archaeologists.

This sword, recovered by a diver working in the silt under the ship's side is unique amongst artifacts recovered as every other metal edged weapon was almost completely destroyed by the sea environment.

The sword is a composite object: the handle is wood, popular or alder; the blade is made of iron with steel cutting edges and the basket hilt is made from quarter inch rods hammer welded together.

After 437 years in the sea the sword is still wonderfully balanced and the blade is sharp enough to cut. Initial chloride removal was completed following 18 months in a sodium sesquicarbonate solution. Following this the sword was placed in wet storage to reduce the chloride levels even further.

The next stage was to dehydrate the sword before finally treating the wooden hilt. After all these years of conservation it has been possible to display the sword in the Mary Rose museum. With all the hard work that has gone into restoring the sword, the Trust needed to ensure it would be preserved for a long time to come.

The sword is on display in it's own sealed case and the humidity levels and temperature are strictly controlled using a Munters MG50 desiccant dehumidifier with a Munters HR1 humidistat.

The relative humidity levels are maintained at 35% RH, which is the optimum level for preserving metals. The Munters dehumidification unit is placed outside the case for aesthetic reasons and the dry air is vented in.

Using Munters desiccant dehumidification the sword will not experience any corrosion, will not have condensation forming on it and as the ambient moisture is removed, the exact conditions are created for preserving this type of meta.

Munters principle:
The system is designed around the desiccant drying rotor, which is the moisture absorbing component at the heart of Munters dehumidifiers. Air to be dehumidified (in the display case) is drawn through the rotor, where moisture is absorbed and the resulting dry air is delivered back into the case.
Simultaneously a separate air flow is heated and drawn through the remaining sector of the rotor. This air removes the moisture from the rotor and is descharged to the atmosphere.
As well as the 500 year old sword, Munters desiccant dehumidification systems are also protecting the pewter case, the swivel gun and drying room.

Benefits

*Prevent condensation

*Arrest corrosion

*Control humidity

*Stop mould

*Extend artifact life