凿沉

凿沉	záo chén	to scuttle (a ship)
凿	záo	(bound form) chisel / to bore a hole; to chisel; to dig / (literary) certain; authentic; irrefutable / also pr. [zuo4]
沉	chén	variant of 沉
沉	chén	to submerge / to immerse / to sink / to keep down / to lower / to drop / deep / profound / heavy