Used on all Catalinas built after about 1986. Any boat with tinted plexiglas fixed ports (deadlights in nautical terms, windows for the rest of us) use this sealant to bond the glazing to the boat. It is an industrial product used to install glass curtain walls in high-rise office buildings.
Early boats had self tapping screws through the plexiglas in addition. Over time the plexiglas was prone to breaking at the screw holes. On later boats, Catalina eliminated the screws. This reduced the breakage problem with no apparent reduction in integrity. It turns out the bond holds more tenaciously than the screws!
This special sealant is also used to install replacement glazing into an aluminum framed forward hatch. It has the right properties for a permanent bond between the plexiglas glazing and the aluminum frame of the hatch.
10.3 oz cartridge. Black.