Some require the drilling of holes into the tank, which can be costly, depending on the reservoir design. Because of drive design, drum types tend to require more elaborate mounting methods and space. Belt, disk, tube and mop drive units consume a moderate amount of space. An advantage of some belt skimmer drives is the use of a flat surface mount or bracket, neither of which require tank modifications. Mounting stands, brackets and adapters help make skimmer installations easier and faster.
Portability is a plus in some applications.
For example, in plants and mobile equipment service shops, a portable skimmer can sometimes service both a parts washer and a drain water retention sump. Belt and disk type skimmers tend to be the best designs for portability, and can be made small enough to weigh only a few pounds. As most hydrocarbons spread fairly quickly over the top of water, it is not necessary to use more of the surface than the skimmer medium contact area. However, a skimmer's design may actually take up more of the surface than the minimum required. A drum skimmer may require up to five square feet depending on drum size.