Docking

Docking (repair) can restore your ships to full health, which costs you fuel and steel.
Larger and higher-level ships take more time to repair. But it is possible to repair a ship instantly by using fast repair material (bucket).
You can shave off the last minute of repair time by switching to the docking screen when a ship has less than one minute of repair time to go.
You start the game with two repair dock slots--you can pay gold (DMM points) to buy keys in shop and expand to 3 or 4 slots.

Repair time

[math]\displaystyle{ \text {Repair time} = \text {HP loss} \times \text {base repair time} \times \text {ship type} + \text {30 seconds} }[/math]

Ship Type	Multiplier
Slow battleship, Aircraft carrier	2
Heavy Cruiser, Battlecruiser/fast battleship, Light aircraft carrier	1.5
Light Cruiser, Destroyer, Aircraft-carrying submarine	1
Submarine	0.5

Battlecruiser/fast battleship: Kongou-class
Aircraft-carrying submarine: I-58 Kai (her repair time will double after remodel)
These are assumed times based on calculations and rounding.
Represented as [minutes]:[seconds]

Lv	Base repair time
1	0:10
2	0:20
3	0:30
4	0:40
5	0:50
6	1:00
7	1:10
8	1:20
9	1:30
10	1:40
11	1:50
12	2:00
13	2:05
14	2:10
15	2:25
16	2:30
17	2:35
18	2:40
19	2:45
20	3:00

Lv	Base repair time
21	3:05
22	3:10
23	3:15
24	3:20
25	3:25
26	3:30
27	3:45
28	3:50
29	3:55
30	4:00
31	4:05
32	4:10
33	4:15
34	4:20
35	4:25
36	4:40
37	4:45
38	4:50
39	4:55
40	5:00

Lv	Base repair time
41	5:05
42	5:10
43	5:15
44	5:20
45	5:25
46	5:30
47	5:45
48	5:50
49	5:55
50	6:00
51	6:05
52	6:10
53	6:15
54	6:20
55	6:25
56	6:30
57	6:35
58	6:40
59	6:45
60	7:00

Lv	Base repair time
61	7:05
62	7:10
63	7:15
64	7:20
65	7:25
66	7:30
67	7:35
68	7:40
69	7:45
70	7:50
71	7:55
72	8:00
73	8:05
74	8:10
75	8:25
76	8:30
77	8:35
78	8:40
79	8:45
80	8:50

Lv	Base repair time
81	8:55
82	9:00
83	9:05
84	9:10
85	9:15
86	9:20
87	9:25
88	9:30
89	9:35
90	9:40
91	9:45
92	10:00
93	10:05
94	10:10
95	10:15
96	10:20
97	10:25
98	10:30
99	10:35
100

Repair cost

See ship list or remodeled ship list for their base fuel cost.

[math]\displaystyle{ \text {Steel} = \text {Base fuel cost} \times \text {HP loss} \times 0.06 }[/math]
[math]\displaystyle{ \text {Fuel} = \text {Base fuel cost} \times \text {HP loss} \times 0.032 }[/math]

Example

Level 67 Kongou with 41/75 HP (34 damage) will have:

Repair time:
- [math]\displaystyle{ 34 \times \text{455 seconds} \times 1.5 + \text{30 seconds} = \text{23235 seconds or 6:27:15} }[/math]
Resource costs:
- [math]\displaystyle{ 90 \times 34 \times 0.06 = \text{183 steel} }[/math]
- [math]\displaystyle{ 90 \times 34 \times 0.032 = \text{97 fuel} }[/math]