Is it surprising that sailors have sore knees of lower backs when they sound so much of their time in unsupportive shoes, with little awareness of their biomechanics and the importance of ankle strength and arch support. This can come from shoes, or it can come from better glute recruitment and correct standing. Why do we spend money on corrective therapists when learning to stand properly and walk properly and wear decent shoes would solve a whole lot of issues.
You can see in these pictures the collapse of the ankle in the left foot – how the foot rolls in. It is not necessary to fill the gap with orthotics, but it is necessary to work on posture and correct the inward ankle roll, though awareness and exercise.