You can upgrade your ships by modernization, which can increase their firepower, armor, anti-air and/or torpedo attack, also, a good way to get rid of unwanted ships.
First pick the ship you want to upgrade, then choose 1 to 5 ships to "merge". You will lose them in the process, make sure you didn't pick the one's you want to keep.
Note
You will lose all modernization upgrades after remodeling. Don't let it discourage you from modernizing your girls though, unless they are close to remodel level.
A consumed ship's equipments get wasted, You will not retain any equipment still equipped on the consumed ship. Remember to remove any valuable equipment the consumable ship might possibly have. Also stock equipment can be broken down for small amounts of material though most likely not worth the effort.
There is a maximum cap for upgrades, you can view the number at Ship Maximum Status.
Modernization can fail with +1 only, see the graph below for details (0 will give you the penguin failure screen, all other results will display as the success message).
Input
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Success
1
2
3
5
6
7
8
9
11
12
13
14
15
17
Fail
0
1
2
2
3
3
4
5
5
6
6
7
8
8
Note: The table is not be used for Luck modernization.
The chance of success is 50% for each stat you're trying to boost with Modernization, i.e. you can attempt to Modernize for +15 firepower +15 armor, but end up with +15 firepower +8 armor as the result.
Luck
Following the December 2013 update, Maruyu can be used Modernization material for +1.2 luck (+1.6 luck if she is remodeled to Maruyu Kai), result will be rounded down after adding random number below 1. You can still increase a maxed-out ship's luck through modernization. Luck does not reset upon remodeling.
Maruyu
1
2
3
4
5
Expected
1.2
2.4
3.6
4.8
6.0
Success
2
3
4
5
6
Fail
1
2
3
4
Chance
20%
40%
60%
80%
N/A
Maruyu Kai
1
2
3
4
5
Expected
1.6
3.2
4.8
6.4
8.0
Success
2
4
5
7
8
Fail
1
3
4
6
Chance
60%
20%
80%
40%
N/A
Note: Although the indicator will display +6 luck for 5 Maruyu Kai before modernzation, it is guaranteed to award +8 luck once carried out.
Ships
All ships will provide a fixed input for modernization.