Question 3439 Deck General

The correct answer is A) vessel. According to the International Regulations for Preventing Collisions at Sea (COLREGS), a non-self-propelled, semi-submersible drilling unit under tow is considered a "vessel" for the purposes of the International Rules of the Road. This is because the COLREGS define a vessel as "every description of water craft, including non-displacement craft and seaplanes, used or capable of being used as a means of transportation on water." The fact that the drilling unit is non-self-propelled and semi-submersible does not exclude it from being considered a vessel under the COLREGS. The other answer choices are incorrect because a "limited vessel" is not a defined term in the COLREGS, a "power-driven vessel" refers specifically to a vessel propelled by machinery, and a "non-displacement vessel" is not a recognized vessel type in the COLREGS.