Can I lose slots?
No, once received, ship slots are permanent, and cannot be sold or lost.
How many ship slots do I have left?
You can see how many slots are not in use at the moment by clicking on the "Filter" button in the lower right corner.
Do all ships need a slot?
No, unlike other Wargaming titles, Premium Ships in World of Warships Blitz do not need a ship slot. So, there is no need to sell a premium ship to make room for a different ship.
How to get a slot?
You can either purchase an additional slot for gold, or free an existing slot by selling one of your ships.