Seaman are very overrated.

As for the sub thing, proper ship placement, as in keeping close enough to your team that they will be able to help you but not so close that you are in the way, will do just as much to protect you from subs as carrying guns will. Instead I would reccomend going for supports. A good engineer will allow you to escape subs along with 2 repair men to keep you healthy.

A restorer is also possible since it is hard to get 900sd on a CV, especially if you have elites. 

For your pilot setup, 2 scouts 6 fighters is ultimatly the better choice. No need to put your fighters in danger of AA if you can handle your scout pilots well.

Well... if you plan to go FW then your crew is the best choice...

6 ft and 2 scouts is the best setup for most players...

but in my consider i run 6ft 1 scout and 1 tb...

scout can be great in pair but they have more fuel than FT so when your scouts runs out of fuel you should set your fp to enemy line just for a moment until your scout reachs the spot (scout load very fast) and that way you can always bring light to your team saving 1 pilot for bombing dutties, and in US TB is way better choice than DB...

besides up to scout 120 your scout will be really fragile and till reach 120 you might use only fighters

for supports on PCV you get 4 slots... 1 in support, 1 in BO (you can use any sailor above 104) and 2 in gunspace...

you can use sonarman, rep, rest, engys. seaman and gunners...

that depends on your playstyle more than anything else... but since SS5 you should consider putting HH (or PHH) on those gunslots... there will be many rooms in wich enemy ss will hunt for you, as you are one of his main target (with enemy SS and BB5/6)

a restorer in BO slot at that lvl will provide something like 430 SD (good base and vetted) making your ship reach 900 SD wich might help u survive 1 or 2 enemy bomber run (and there will be a lot of those)

an Engy will give your ship a lot of speed (from 42 to 40 depending on armor) and OH time and you might need it to dodge torps, bombings, and scaping from some ships, but in my personal choice if you need to dodge those your battle is lost and in GB there is no need to save the ship for next battle unlike in HA.

A rep its in my consider a bad choice, it will give you good rep hability, but if you have to choose only one (and in CV you have) SD with bad rep its better defense than good rep with low SD.

Seaman its a Must... its not overrated, it will give you something like 5 to 15% boost depending on stats lvl and vetts... you should consider a rep with +12 fighter+10 or more rest. and +10 or more rep.

Sonarman in my consider is the fail choice... if you need to spot a ss in order to hunt it with those many HH slots then start over again... just shoot in gradual till get him and save the slot for something more important like a Rest/engy

setup:

Sup: fighter / fighter / fighter / fighter / fighter / fighter / scout / scout(or TB) / Seaman

BO: engy (for HA) / restorer (for GB)

gun slots : HH (GB) PHH (HA) with 2 Gunners, of course

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final note: no need for elite gunners or restorer. with base +12 rest or +11+11 gunners you will do fine (BVE them)

6ft 2scout is the better setup. I agree seaman are very overrated

I personlly use 6fts, 2scouts, 1BO, 2 gunners using HH, and a engineer (or rep) for my CV6.

If you are using a PCV and don't need to level the BO, then put an engineer on the BO spot and you can add an extra rep on the support.