In pre-fire safety checks, what needs to be ensured about the cannon?

Ensuring that the cannon is locked to the baseplate during pre-fire safety checks is crucial for maintaining stability and safety while operating the mortar. This locking mechanism prevents any unintended movement of the cannon when it is fired, which can lead to improper targeting or potential accidents. A secure connection between the cannon and the baseplate allows the mortar to absorb the recoil force correctly, ensuring consistent performance and enhancing accuracy. Moreover, this connection contributes to the overall operational safety of the crew and the equipment.

Each of the other considerations is still relevant to safety, but they do not directly ensure the stability and operational integrity during firing operations as the locked connection does. Checking for obstructions is necessary for safe firing but does not impact stability post-firing. Similarly, while discussions about baseplate properties or positioning may arise, they are secondary to the critical nature of ensuring the cannon is firmly secured to the baseplate before any firing operations commence.