Parametric Estimation of Tanker Deckhouse Volume from Direct General Arrangement Measurements

This study analyses the parametric scaling of deckhouse volume ( Vdh) and engine casing volume ( Vec) of oil tankers, based on direct measurements of general arrangement (GA) drawings of 80 vessels from Handysize to VLCC in RINA Significant Ships (1991–2019). Power-law regression yields Vdh = 76.55 ×DWT0.3667 (R² = 0.710, n = 80), Vec = 1.37 ×DWT0.6062 (R² = 0.641, n = 77), and Vtot = 56.82 ×DWT0.4150 (R² = 0.757, n = 80); all exponents are well below unity. The Vec/ Vdh ratio shows a discontinuous step from 0.14 at Handysize to 0.29-0.36 from Panamax upwards, with no significant temporal trend (p = 0.850). Applying the multiple regression framework of Frančić et al. (2023), established for tanker lightship displacement (R² up to 0.99), to Vdh yields R² = 0.68, a gap of about 0.31, i.e. an indication of component-specific applicability between mass-derived and space-derived metrics. Volume elasticity decreases monotonically relative to the Panamax reference (Aframax 0.56, Suezmax 0.42, VLCC 0.29), and the deck count saturates at five to six decks beyond Handysize. Sub-linear scaling reflects four drivers: engine room bulkhead alignment, longitudinal stiffener alignment, forward visibility, and manning saturation. The estimators support early-stage volume estimation.