Which statement best differentiates Major ATON structures from Minor ATON structures?

Which statement best differentiates Major ATON structures from Minor ATON structures?

• A. Major are simple and require little engineering; Minor are highly complex
• B. Minor are more complex than Major
• C. Major are complex and require engineering; Minor are relatively simple, made of wood or concrete piles, steel piles, or other steel shapes and can be lighted or unlighted
• D. Major are only used on waterway channels; Minor are for harbor areas

Answer: (C)

The key idea is the difference in design and construction effort between Major and Minor ATON structures. Major ATONs are built to meet higher loads and harsher conditions and serve critical navigation needs, so they require formal engineering to design, approve, and maintain. Minor ATONs are simpler and lighter in construction, typically made from wood or concrete piles, steel piles, or other basic steel shapes, and they may be lighted or unlighted depending on the plan. This combination—engineering-driven complexity for Major and simpler, more readily built structures for Minor—best differentiates the two. The other statements misstate the relationship (for example, Major being simple or Minor being more complex) and don’t fit how these aids are designed and implemented.

The key idea is the difference in design and construction effort between Major and Minor ATON structures. Major ATONs are built to meet higher loads and harsher conditions and serve critical navigation needs, so they require formal engineering to design, approve, and maintain. Minor ATONs are simpler and lighter in construction, typically made from wood or concrete piles, steel piles, or other basic steel shapes, and they may be lighted or unlighted depending on the plan. This combination—engineering-driven complexity for Major and simpler, more readily built structures for Minor—best differentiates the two. The other statements misstate the relationship (for example, Major being simple or Minor being more complex) and don’t fit how these aids are designed and implemented.