Question 1194 Deck General

The correct answer is C) not less than 2.5 inches. According to the regulations for tank barges constructed on or after July 1, 1951, the required vent size for each cargo tank is not less than 2.5 inches. This is specified in 46 CFR 39.20-9, which sets the minimum vent size requirements for tank vessels. The other options are incorrect because A) 1.5 inches is too small, B) 2.0 inches is also too small, and D) 3.0 inches, while acceptable, is larger than the 2.5 inch minimum requirement.