The starting principle

The Navigation Rules are collision-avoidance rules, not a system for claiming privileges.

Every vessel remains responsible for:

maintaining a proper lookout

proceeding at a safe speed

determining whether risk of collision exists

taking effective action in ample time

accounting for special circumstances

avoiding collision even when another vessel has failed to perform its duty

Rule 2 also makes clear that ordinary compliance does not excuse a vessel from precautions required by the ordinary practice of seamen or by special circumstances.