Tonnage tax regime defines qualifying ships and companies to compute tonnage income under special provisions. Section 115V defines foundational terms for the Chapter XII-G tonnage tax regime: contractual forms like bareboat charter and bareboat charter-cum-demise; vessel categories including seagoing ship, factory ship, fishing vessel, pleasure craft, and inland vessel; administrative references such as the Director-General of Shipping; and tax concepts including tonnage income, tonnage tax activities, tonnage tax company (a qualifying company with the tonnage tax option), and tonnage tax scheme for computing profits from qualifying ships.