Locate the indicated fleet in the grid. Each piece of a ship occupies a single cell. A cell that does not contain a ship piece is considered "sea". Ships can be rotated. Ships do not touch each other, not even diagonally (that is, if two ship pieces are in adjacent cells, they must be part of the same ship). The contents of some cells are given for you. Each number to the right and bottom of the grid reveals the number of ship pieces that must be located in that row or column (including any that might be given for you).
(Rules and example (standard fleet) from PGP IB)
- In most puzzles the fleet consists of 1 battleship (1x4), 2 cruisers (1x3), 3 destroyers (1x2) and 4 submarines (1x1). This set of ships is often called the standard fleet.
- Smaller fleet of 1 cruiser, 2 destroyers and 3 submarines is commmon for a fleet in example puzzles.
History of the puzzle
Pencil-and-paper game version of Battleships traces dates from World War I. Solitaire version is invented by Jaime Poniachik (Argentina) and was first featured in 1982 in the Argentine magazine Humor & Juegos under the name "Batalla Naval." 
Appearances in the past WPCs
Listed here are appearances of classic to almost-classic Battleships. For variants, see list of Battleships variants#Appearances in the past WPCs.
- WPC 2019/Round 3 (Permaculture hybrid with Anglers) by Silke Berendes
- WPC 2019/World Cup Round 1 by Roland Voigt
- WPC 2019/Round 4 by Roland Voigt
- WPC 2019/Round 9 by Ulrich Voigt
- WPC 2019/World Cup Playoffs by Ulrich Voigt
- WPC 2017/Round 3 by Ashish Kumar
- WPC 2017/Round 10 ("Optimizer") by Prasanna Seshadri
- WPC 2017/Round 22 by Amit Sowani
- WPC 2016/Round 2 by Matej Uher
- WPC 2016/Round 9 by Matúš Demiger
- WPC 2014/Round 3
- WPC 2014/Round 7
- WPC 2013/Part 2
- WPC 2013/Part 6
- WPC 2013/Part 8
- WPC 2012/Part 5
- WPC 2012/Part 10
- WPC 2011/Part 2
- WPC 2010/Part 2
- WPC 2010/Part 6 ("Even/Odd")