For a given shell diameter and tube sizes for a shell-and-tube heat exchanger, which tube pitch pattern would be the most compact design allowing for the most tubes?

Correct Answer: Option C — Triangular tube pitch

Triangular pitch allows for the highest density of tubes within a given shell diameter because the tubes are arranged in an equilateral pattern. This configuration maximizes the total heat transfer surface area, making it the most compact design choice for marine heat exchangers where space is at a premium.