🔍 Key Concepts

• Typical pressure ranges for starting air systems on motor ships • Normal working pressure for ship’s service/working air systems used for tools and controls • Purpose of emergency and topping-up compressors compared to the main air system

💭 Think About

• Think about which systems on board need the highest air pressure (e.g., to turn an engine) versus which only need moderate pressure (e.g., tools, valves) • Ask yourself: which compressor normally supplies air that is directly used by shipboard consumers like pneumatic tools and control systems? • Consider whether an emergency or topping compressor is usually designed to reach the same maximum pressure as the main starting air bottles, or just to maintain / back up that pressure

✅ Before You Answer

• Recall the usual starting air pressure range for large diesels (is it closer to 100 psig or several hundred psig?) • Review what ‘topping air’ means in relation to already-pressurized air bottles • Match the answer choice that is typically associated with a general service/work air line around 7 bar (~100 psig), not a high-pressure starting air line