It called my attention there are not a single guide about armoring ships so i decided to write one for new players or for people who never read a thing about the matter.
0-Impacts of shells.
There are 2 types (main types) of shell impacts:
Deck-shots hit you on the deck of the ship. You can recognize them when white numbers pop-up when shells hit.
Belt-shots hit you on the belt of the ship. You can recognize them when green numbers pop-up when shells hit.
What determinates if a shell is going to hit in deck or belt? Well, there is certain randomness but it's mainly determined by the angle the shell was shotted. If it was shoted at high angle there will be more probability of hitting in deck and it it was shotted with a low angle there will be more probability of hitting you in belt.
What angle can be taken as a reference? Well, let's say around 20 degrees. But sometimes you can shoot at 30 degrees 9 shells and got 7 belt impacts, other times you can shoot at 15 degrees 9 shells and get 7 deck impacts. There is no a "hard" frontier, its random. I even have seen sometimes belt impacts shotting at 45 degrees, but its quite rare.
The damage of the shell also depends on angle. It works like the damage of a shell has a "kinetic" component and an "explosive" component. Belt-impacts will make more damage as lower the angle (impacts go more perpendicular to the belt of ship, kinetic damage is higher) and Deck impacts will make more damage as higher the angle (they land more perpendicular to the deck of the ship, kinetic damage will be higher).
1-Armor types
Deck.
As its name indicates it works against deck shots.
Obviously most of the hits a BB receive are on deck, it's a rare battle situation being fighting under 20 degrees.
Deck armor works the way or you bounce a shell (0 or very low damage) or you eat the full damage completly.
So putting small amounts of deck is completly uneffective, there are urban legends around putting a small amount reduces crew deaths. Everyone can believe what they want.
So, what is a "decent amount"?. Some references, they are just references:
With 5.0 on deck you can bounce CA (non-PCA) shells at max range, i think with this value you can bounce in deck any FF/DD/CL/CA ship. But well, that's not quite useful, isn't it?
With 8.0 you can bounce most of PBB/BB123 at max. It's just an aproximation, maybe there can expeptions like NorCar (45 degree guns) or Nagato (43 degree guns).
About BB4 the "magical" value was 9.1 UK deck armor. With that you can bounce every BB4 shells at max range except Yammy and Stalingrad.
About BB56 with around 11.0 deck a QV can carry you can bounce KM BB56, MN BB56, UK BB6 and RM BB56.
So, with those references it's up to you to see if you want to put deck armor or not, but i think is fair to say in GB is a bit stupid to put less than 8.0.
Belt.
As it name indicates it works against belt shots.
The effect of belt against shells is completly useless, so putting belt for that is a nosense. Very few ships can hold large amounts of belt. The only ships where this is good i found where Prinz Eugen and Omaha on blitzs.
The most important effect of the belt in game is that putting 0.2 on belt halves the torp damage.
Over that amount there is no significative reduction.
So, put 0.2 of belt in all your ships, its not a recommendation, it's a must.
Bulk head.
When your DP bar is under certain frontier value you loose overheat capability.
That value is determinated with the "defense value".
Putting Bulk Head increases that value, allowing your life bar go lower without loosing overheat capability.
Unfortunately this armor weight is too high and the effect on that is too low. Both things. So it's completly uneffective.
Don't put Bulk Head armor on your ship.
Bulge.
Bulge works against torps.
This is the only type of armor that is "spent" when you receive impacts.
IJN bulge was the most effective if i remember well.
2-Configurations.
Configuration of the 99% of the ships.
-Put all your sailors, guns, engine, FCS, HHs, shells and everything on your ship.
-Go to armor panel.
-Put 0.2 belt.
-Put the rest on bulge until you loose a knot, then go back, recover that knot and press ok. If you are a CV maybe you would want to sacrifize some knots in exchange for more bulge.
Configuration for deck-armored ships.
There are people that puts 0.2 belt and the rest of displacement on deck and there are peop
