Which variable factor affects the initial lashing requirements aboard Ro-Ro vessels?

Correct Answer: Option A — Number, position and angle of lashings

Initial lashing calculations on Roll-on/Roll-off vessels directly depend on the geometry of the securing arrangement, specifically the number, position, and angle of lashings relative to the cargo unit's axes to effectively counteract transverse and longitudinal dynamic forces during heavy rolling and pitching in accordance with Cargo Securing Manual guidelines.