Yashio Riho♀

A girl that is very skillful with machines (or should I say, she has a machine fetish). Timid and afraid of talking to people, but once the subject of machines is brought up, she becomes more talkative. She is very detailed in serial numbers and diving suits, not to mention good at maintenance work. Rio's wish is to become an ocean engineer. However, Rio receives the worst times in the training classes and often gets punishments for failing, such as cleaning the pool and bathrooms. Rio, along with the protagonist, are both bad swimmers.

[Edited from dnandre's review]