A small number of two-part epoxy coatings have the unique feature of being able to be applied underwater. Common applications include coating piers, pilings, pools, tanks, etc. In many areas of the globe, humidity levels are often well above 75% nearly all of the time. With such high moisture levels, most dry surface paints will have a much reduced surface bond which can result in premature blistering or coating failure. Simply put, moisture, in whatever form, is a primary reason for coating problems. Underwater (i.e. wet surface) epoxies avoid this area of concern. These epoxies can, of course, be used on dry surfaces much like any other coating. Besides those already mentioned, other places you are likely to find underwater epoxies include the inside and outside of ships, inside manholes, on cooling towers, piers and pilings, and tanks, pits and sumps of all kinds, as well as on floors with vapor transmission problems.
Source: epoxyproducts.comAdded: 14 June 2006