For safety regulations, how must Hull ID numbers be displayed?

Hull ID numbers are crucial for identifying vessels and ensuring compliance with safety regulations. They must be displayed in a manner that is easily visible and legible, which is why the correct choice emphasizes the use of block letters. This format enhances visibility from both sides of the vessel, making it simpler for authorities and other boaters to identify the boat quickly.

Displaying the Hull ID number in block letters on both sides of the vessel adheres to federal and state requirements, giving it a standardized format that aids in identification for safety checks, law enforcement, and in cases of theft or loss. It's important for the numbers to be prominently displayed so they can be recognized easily, which further bolsters compliance with safety measures.

Other options, such as using a small font, limiting the display to just the bow, or not ensuring color contrast with the hull background, could lead to difficulties in visibility and identification, making the vessel less secure and potentially violating regulations.