At all times. According to the Navigation Center of the United States Coast Guard (Rule 5), “every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.” To be clear, this does not just refer to USCG documented vessels. This refers to any boat on the water of any size. In this context, the phrase “look-out” is a noun, referring to someone who watches and listens so as to be fully aware of the vessel as what happens in its vicinity. This person should always be ready to act and not just to watch. In just about any size vessel, the look-out is not the captain or person at the helm, but rather, someone towards the front of the boat. Typically, they are to be at a remove from distractions on the vessel so that they can better focus on what is ahead, what is around, what is on the water, etc. Neither Rule 5 nor any other rule stipulate where the look-out must be. However, common sense and competent navigation suggest that the look-out be placed anywhere they could best be equipped to hear and see anything that could potentially collide with the vessel. If your vessel is eligible, you can use this link to apply for vessel documentation.