"抓斗式挖泥船" can be translated into English as "clamshell dredger" or "clamshell bucket dredger".
"Clamshell" refers to the clamshell-shaped bucket used for scooping up mud or sediment.
"Dredger" (or "dredge" when used as a noun in some contexts, though more commonly as a verb) is the term for a vessel or machine used for dredging.
Both translations are widely accepted and used in the maritime and dredging industries.