Here's why:
* Collective nouns are specific to a single species or group: For example, we have "pride" for lions, "crew" for sailors, "flock" for birds, etc.
* Lions and sailors have distinct roles and habitats: It's unlikely you'd find these two groups together in a natural setting.
Therefore, you could simply use "group" or "collection" to refer to a gathering of lions and sailors.
For a more imaginative approach, you could create your own collective noun, perhaps something like:
* A "roar" of lions and sailors (combining the lion's sound with the sailors' nautical theme).
* A "voyage" of lions and sailors (referencing the sailors' journey and the lions' roaming nature).
Ultimately, the best option depends on the context and the desired effect.