M_Boats: cam cleats

Quick question. Would cam cleats mounted on the cabin top be substantial enough to serve as a clutch for the main halyard?? I was planning on putting a block at the base of the mast with a turning block on the cabin top and then running it aft through a cam cleat. I haven't had any problems just reaching over the cabin hatch to cleat the halyard off on the mast cleat, but started thinking about what I would do in an extreme emergency and needed to drop the main in a split second. Thanks, Joe