Ask the COC. I am a retired MCPO and am now a contracter that still does a lot of shipboard work. Last week I was in Norfolk working on a DDG and asked the Senior Chief if it was OK vice going out with the smokers. He told me to go for it. I did, but did so discretely. Remember if you don't ask, and get caught DC3, the consequences aren't gonna be cool. So know what your COC's policy is and then follow it. If you are told no, understand that there will be consequences if you do it and are caught.
I will be underway again next week on a CG outta Norfolk... I am curious as to what reaction I will get. If need be I will just stealth vape... but so far no COC has ever had an adverse reaction when I ask.