What precaution should be taken when warming up the boat engine?

Keeping the boat tied to the dock while warming up the engine provides stability and ensures that the vessel remains secure in a predetermined location. This precaution is critical for several reasons. First, a tied boat minimizes the risk of drifting away or colliding with other vessels or the dock as the engine warms up. Second, it allows the operator to monitor the engine's performance without the immediate concern of navigating or maneuvering the boat. This is especially important for ensuring everything is functioning properly, including steering mechanisms and safety equipment, before embarking on a voyage. While other options involve loosening lines or moving away from the dock, they do not offer the same level of safety and control during the engine warming process.