I have a clean agent FireBoy cylinder operated by a fusible link sitting in my garage. It’s from a previous boat. I need to do the calc, but I would guess it will protect about 60 percent of my currents boat engine room space so I would need a second bottle. I realize the engine would ingest a large portion of the gas if it operated, thus greatly reducing the chances for suppression, but I have had mixed fillings about installing the interlock to shut down the engine. If it were a gasoline engine, yes. But diesel has a flash point higher than the ambient temp of my engine room space (not a guarantee against a fuel fire, just a fact regarding the much lower frequency of occurrence). I check the space often, and don’t take any chances when it comes to fuel, leaks, electrical systems, etc. I respect others people’s decisions to interlock these for engine shutdown, but I am not there yet.