Seawater is an extremely persistent, surprisingly corrosive force that causes a multitude of complex problems when it comes to use and maintenance of maritime vessels. Any equipment that is exposed to seawater on a regular basis is especially vulnerable and must be rigorously maintained if it is to function reliably. At the same time, any lubricants that come into contact with seawater need to be specially formulated to minimize their environmental impact as well as to avoid exposing sailors to hazardous volatile organic compounds (VOCs). This article highlights several environmentally friendly and sailor-safe grease solutions for potential use on submarines and other military (and nonmilitary) sea systems
THE CHALLENGE TO KEEP MOVING PARTS MOVING
Keeping all of the moving parts of seafaring vessels adequately lubricated is an especially complex problem, particularly when the vessel is a submarine. Properly greasing actuated parts (such as the hatch shown in Figure 1) can greatly lengthen service life and ensure equipment reliability, but finding an environmentally friendly grease that is reliable when submerged in salt water, does not off-gas (i.e., emit harmful fumes), and is not prohibitively expensive is a difficult task.
Aquatic ecosystems are delicate and especially susceptible to pollutants, but ships of all kinds require lubricant on a variety of submerged parts to function properly. The Environmental Protection Agency (EPA) issues any vessel over 79 ft long a Vessel General Permit (VGP) to regulate the amount of pollution produced by ships. These permits allow incidental discharge of wastewater and lubricants through the course of normal operation, while imposing limits on this discharge and having specific standards that must be met for any lubricant that comes in contact with the water. To qualify for a VGP, commercial vessels must use Environmentally Acceptable Lubricants (EAL). According to the EPA website, EALs are biodegradable, minimally toxic, and nonbioaccumulative (i.e., fish and other ocean organisms will not absorb pollutants from the lubricant at a faster rate than they can excrete them). Accordingly, many of the most common types of lubricants, such as petroleum-based oils and mineral oil, are excluded under these regulations. read more
Article from DSIAC – Defense Systems Information Analysis Center