As with any complex piece of machinery, the replacement costs of boilers can be prohibitive. Highly useful in ship and train engines as well as for building heating, it can be useful to keep on hand stored boilers. Mothballing old boilers for storage can be a laborious process, but when an integrated part of ship mothballing or other defense related storage activities it can offer distinct advantages down the line.
Naval boilers mothballing has been around since the advent of coal fired boilers in the steam ships of the nineteenth century. Naval vessels have always been expensive to build and maintain, and when steam boilers were used to power ships yet another added piece of technological wizardry became an essential component of naval maintenance. Ships ranging in size from destroyers to massive dreadnoughts and aircraft carriers all carried a complement of boilers. Mothballing ships had been around for some time in order to preserve expensive, well crafted ship hulls in case they were needed and mothballing their boilers is a logical adjunct to ship mothballing.
Mothballing boilers serves two primary purposes. First is to keep the main power supply of a mothballed ship available in case the vessel is pulled out of mothballs for upgrades or sale. An excellent example of this is the re-activation and upgrading of the Iowa Class battleships in the 1980's. A World War Two design, fears of increased Soviet sea power brought them out of mothballs. Another major function of boilers mothballing is for use in compatible vessels in need of repair. Navies have long been innovators when it comes to recycling. Parts from an old ship are often salvaged and integrated into a newer model or used as spare parts to keep an older vessel running. Mothballing a vessel's boilers keeps them available in case they could be of use in just such a manner.
Not simply applicable in defense industries, boiler mothballing can be useful in civilian sectors in order to keep a ready supply of spare machinery available in case of damage to or malfunction of a boiler currently in use. A building boiler that is responsible for the heating of water and space that fails in the winter months generally needs to replaced as soon as possible. Having boilers mothballed that can be quickly pulled out of storage and used to replace the malfunctioning unit is often the optimal solution