As Kinlu said, tappo wants something like a proof.
We tested Air reload speed on a sub, with and without Seaman in the support slot:
No significant difference.

Same with CV, no remarkable difference in the ammount of planes shot down.
So if the Seaman does something it is below the influence of sailor base and
ammount of vets.

I didn큧 made any spreadsheets and did not test it 100 times for a proof.

Boosts ability. However doesn't go over the cap.

seaman is very useful on a cv crew. it helps to increase your crew's ability, so if you
have a seaman on your cv, your fts will do better.

Hope i can help

Fireson

It is useless even if it is activated -.-

I assure you that tappo knows very well what seaman are supposed to do.

The way I read it he wants proof. And you did not deliver.

ok... i will answer your question , unlike the jerk above me .

seaman boost your crews stats , and yes they are activated...

This topic.

Why did you make it? I have not seen you play for like a year. Why do you care
about seaman?