None of the 25mm meet the SOLAS standards. There is also the issue of a single pistol or firing tool. In the dark, rough water, confusion of the disaster.. they can fail, corrode or simply get dropped into the sea. That is why the knowledgeable and prudent mariner stocks his disaster grab bag and life raft with single use handheld SOLAS certified flares. It you want to get current or up to speed with this kind of stuff consider taking the next Safety at Sea seminar at your local yacht club. For skippers the "Hands On" is the way to go.

http://www.ussailing.org/education/safety-at-sea/

Link Safety at Sea Seminars