For what purpose are smoke periscopes fitted on naval boilers?

Smoke periscopes on naval boilers are primarily used to observe the quality of the combustion gases produced during the combustion process. The functionality of these periscopes is crucial for ensuring that the fuel is being burned efficiently and effectively. By allowing operators to visually assess the smoke output, they can determine if the combustion process is optimal or if adjustments need to be made to improve fuel efficiency and reduce emissions.

Monitoring combustion gases helps prevent issues such as incomplete combustion, which can lead to excessive smoke and pollutants, as well as ensuring the operational efficiency of the boiler. This direct observation aids in troubleshooting and maintaining proper combustion conditions, which are vital for the safe operation of the boiler system.

While the other options present important aspects of boiler operation and maintenance, they do not directly relate to the specific purpose of smoke periscopes. Checking for leaks, measuring temperature variations, or even monitoring fuel efficiency are typically managed by other tools and systems designed for those specific functions.