A composition for disinfecting removable dental appliances, which includes a chloramine bleaching agent, and an amino-substituted alkylsulfonic acid. In some embodiments, the watercraft cover’s support structure is normally irreversibly integrated into or retained by a sheet of the watercraft cover, and the support structure and the sheet are collapsible together for portability without separating the support structure and sheet. A turbofan is arranged within the fan nacelle and upstream from the core nacelle for generating the bypass flow. The protective agent includes hydrogenated vegetable oils andor hydrogenated animal oils having melting points of greater than 50\xb0 C.