Is there any other preposition I can use instead of "on" here?
Native speaker’s answer
Rebecca
The preposition "on" here is used to describe the state of voyaging or to mean "during" a voyage. There isn't really another preposition that you could use instead of "on" that would fit in this context. Prepositions in English are very idiomatic, so it isn't common to use a different preposition to describe the state of something in this context.