Besides the classic 10x10 Battleship puzzles, there are many fascinating variations. I never cease to marvel at the ingenuity of puzzle makers in creating new and challenging variations of Battleships. Here's a list of them for your enjoyment!

Description	Comments
Tetris Battleships	Like classic Battleships, only where the pieces are consist of five different tetrominos (four-squared polyomino). It has a distinct feel. I've seen one example so far in GAMES Magazine's December 1995 issue, page 83.
Digital Battleships	The initial puzzle board has a digit in each cell, and the board hides a classic fleet of ships. The tallies equal the sum of digits corresponding to ships. All other digits are "red herrings". I first saw this variation in the 9th World Puzzle Championship qualifying test. Here's the puzzle and Matthew Daly's analysis. Check out this complete analysis and solution of a Digital Battleships puzzle.
Do or Die	The object is to place six dice in the grid such that the tallies, which are the sum of the die pips, are correct. I first saw this variation in the 9th World Puzzle Championship qualifying test. Here's the puzzle and Matthew Daly's analysis.
Hexagonal Battleships (classic) Hexagonal Battleships (from 9th World Puzzle Championship) Hexagonal Battleships (incomplete tallies) Hexagonal Tetrominoes (from 13th World Puzzle Championship)	Similar to classic Battleship, but the board grid consists of hexagons. The September 1999 issue of GAMES Magazine has an excellent exposition of solving Hexagonal Battleship puzzles, contributed by Gavin Stark. The May 1999 issue of World of Puzzles shows a hexagonal battleship puzzles with several tallies missing.  Here is the original puzzle together with its solution. The May 2005 issue of "GAMES World of Puzzles" had Hexagonal Tetrominoes, a Hexagonal Battleship variant from the 13th World Puzzle Championship.  Here is the original puzzle and its solution. Yoogi Logic Software offers Hexip, a Windows program for playing Hexagonal Battleships (see my review).
Wildcard Battleships	Same as classic Battleships, but all ship segment hints are wildcards, not the actual ship segment.
Erich Friedman's Battleship puzzles	Erich Friedman's interesting site features many of his original puzzles, including his Battleship puzzles. There are five 3 x 1 ships hidden in a 5x5 grid, each ship with a different number from 1 to 5. The numbers at the sides of the square give the sum of the numbers on all the ships in that row or column. Each puzzle has a unique solution. Can you find it? Here's a solved example from Erich's site: See also Erich's extremely original Battleships variants, puzzles 5 - 14 (many which were featured in the 9th World Puzzle Championship [October 2000]).
Erich Friedman's Square Puzzles	Erich has added a new variation to his site: square puzzles. This puzzle type is a more generic variation of the Squared Battleships puzzle. In Squared Battleships, the types and number of ships in the fleet are known. In Square Puzzles, all that is known is that all ships are squares.
Tic-Tac-Town	Featured in Games Magazine's May 1999 issue (page 41).
Lost Armada	Featured in GAMES September 2000 (Jane Wykes). Each Armada consists of four vessels -- a Battleship (five squares), a Cruiser (three squares), and two destroyers (two squares). The ships are positioned horizontally, vertically, or diagonally. The ships never occupy adjacent grid squares, not even diagonally.
Classic Battleships with wildcard hints
Foggy Battleships	Featured on Marcelo Inglesias's puzzle blog site "Acertijos y pequeños enigmas", Battleship puzzle XIII.  In this variation, there are no row or column counts.  Instead there is a plethora of ship segment hints given.  The weather is foggy, however, and it is difficult to make out several of the hints -- you know they're ship segments but you're not sure which segments they are.
Minesweeper Battleships	See also Marcelo Inglesias's blog site, Battleship puzzle VIII.
Lighthouse Battleships (aka Battle Lines)	Created by the prolific puzzle inventor Trevor Truran.  See Puzzler Media web site for such a puzzle and a solver's guide (cached).
Paint-By-Numbers Battleships
Name Game
Rain Clouds	This intriguing puzzle is, in essence, a Battleship variant.  It has featured several times in GAMES Magazine, in Dave Tuller's / Michael Rios's "MENSA Math & Logic Puzzles" and "The Ultimate Clever Puzzle Book", and now on the site of the Russian puzzle club "Diogen" (see their Clouds puzzle and solution).
Tents (in Dutch: Tentje-Boompje) Tent Pairs Pentomino Camps	Tents An increasingly popular puzzle, this puzzle has been printed in numerous puzzle magazines and books (e.g., Zeeslagje, Tuller and Rios's "Mensa Math & Logic Puzzles").  Here's a description of the puzzle: Locate the tents in the grid. Each tree is connected to exactly one tent, found in a horizontally or vertically adjacent square. Tents do not touch each other, not even diagonally. The numbers outside the grid reveal the total number of tents in the corresponding row or column. Here are some links to puzzles and solutions: Four puzzles from the GAMES World of Puzzles magazine (November 2000) An interactive online version (puzzle and solution by Dave Tuller) Here's a newsgroup discussion about the Tents puzzle and other variants. Tent Pairs There is a Tents variation located on the Diogen puzzle site entitled "Tent Pairs".  The description is: There are some trees on the grid. Locate two tents near to each tree so that they touch the tree on the edge or at the corner. Tents on the grid can not touch each other, not even diagonally. The numbers on the sides reveal the number of tents on the respecting row or column. Here's their original puzzle and its solution. Pentomino Camps Featuring for the first time at the 13th World Puzzle Championship (October 2004), this variation of Tents has the following description: Place the Pentominoes in the grid so that each tent is adjacent to its own tree.  Pentominoes cannot touch each other, not even diagonally.  Pentominoes can be rotated, but not reflected. Click for the original puzzle and its solution.
House-Tree-Animal (in Dutch: Huisje-Boompje-Beestje)	A variant of the Tents puzzle (created by Karen de Vries-Gerrits?).  Here's what Dave Langers writes in a newsgroup thread: In Holland we have (or at least had) monthly editions in which I have seen such puzzles. A personal webpage in Dutch containing a similar puzzle is http://members.lycos.nl/puzzel/logica.html#Puzzel3.  I suggest you mail the author of this page for more information on this type of puzzle. All the way at the bottom of the aforementioned page you'll find a diagram, with the following text (translated):  House-Tree-Animal In the diagram, 16 connected triplets have to be drawn. A triplet consists of a house, a tree and an animal, in which the tree always is at the centre. Similar symbols can never be found in adjacent squares, not even diagonally. The three symbols can be placed horizontally, vertically, or 'cornerwise', but not diagonally. The digits on the right and bottom indicate the number of symbols in the respective row or column.
At the Right Place	Featured in the 4th World Puzzle Championship, found in GAMES Magazine (March 1996, page 35)
Squared Battleships For a related variant, see SquareBox.	From the 9th World Puzzle Championship (October 2000). Check out this complete analysis and solution of a Squared Battleships puzzle.
Square Box	First published in the 13th PQRST Puzzle Championship, this is a variation of Squared Battleships. While Squared Battleships has a known fleet to find, Square Box does not specify the fleet to find.  All you know is that (a) all ships are squares, (b) ships cannot be adjacent, even diagonally, and (c) The row and column tallies denote the number of segments in each row/column. Here is the original puzzle and its solution.
Tangram Battleships	From the 9th World Puzzle Championship (October 2000)
Ship Battleships	From the 9th World Puzzle Championship (October 2000)
Easy As Battleships	From the 9th World Puzzle Championship (October 2000).  See also Marcelo Inglesias's blog site, Battleship puzzles XI and XII.
Crowded Battleships	From the 9th World Puzzle Championship (October 2000)
Weighted Battleships	From the 9th World Puzzle Championship (October 2000)
Retrograde Battleships	From the 9th World Puzzle Championship (October 2000)
Either/Or Battleships	From the 9th World Puzzle Championship (October 2000).  See also Marcelo Inglesias's Either/Or puzzle displayed on JuegosDeIngenio.org.
Diagonal Battleships	From the 9th World Puzzle Championship (October 2000)
Triangular Battleships	From Ed Pegg Jr.'s excellent puzzle site: (http://www.mathpuzzle.com). From the World Puzzle Championship 2000 page.
Alphabet Battleships	This variation was created by Tim Peeters (first featured at the 2001 Dutch Puzzle Championship): As in Classic Battleships, ships cannot touch each other, not even diagonally. The board, however, is filled with random alphabetic characters. You know that every character of the alphabet is used exactly once. Be sure to check out Tim's excellent puzzle site!
3-D Battleships	A Battleships puzzle set in three dimensions. From the 2001 MIT Mystery hunt. "The MIT IAP Mystery Hunt is an annual puzzle competition held at MIT during the January Independent Activity Period (IAP). The competition challenges each team to solve a large number of puzzles which lead to a coin hidden somewhere on-campus. This site is here to entice you to join the fun, to help you find puzzles on the web, and to help with administration during the hunt. Feel free to look around."
MiniZeeslag ("Miniature Battleships" in Dutch)	Miniature (6x6) Battleships board with incomplete tallies. Featured in the Dutch publication "ZeeSlagje"
MaxiZeeslag ("Large Battleships" in Dutch)	Very large Battleships board (larger than 10x10), usually non-rectangular in shape, with correspondingly larger ship fleets. Featured in the Dutch publication "ZeeSlagje"
Superzwaargewichten ("Extreme Heavy Weights" in Dutch)
Vijandelijkheden ("Armed Hostilities" in Dutch). Also known as "Black and White" Battleships.	Very large Battleships board. The original twist is that there are two fleets (black and white) hidden on the board. There are separate tallies for the black and white fleets. No ship, even from different fleets, is adjacent to another ship. This puzzle type in 8x8 boards has appeared in GAMES Magazine (submitted by Moshe Rubin).  Here's the column as published in the February 2003 World of Puzzles (it's a bit messy -- the Mrs. got to it first :-) ).  Here's a cleaner copy as submitted to World of Puzzles. A Japanese site, belonging to Takahiko Siato, has produced 8x8 boards with a variation: ships of different fleets may be adjacent. The 16th Japanese Puzzle Championship features a 13x13 Black-and-White puzzle.  Here is the original puzzle and its solution (here are links to the full set of puzzles and solutions). This puzzle is a variation of the "Black and White" genre.  The 13x13 puzzle has a slightly different fleet (i.e., no submarines), but the real "kicker" is that the white fleet's column counts are purposely not given!  So the solution should make use of the fact that none of the white ships can be shifted horizontally (otherwise there would be multiple solutions -- see discussion about assuming uniqueness).
"T It Up" Battleships	From the USA/Canada/Finland Team Qualifying Test (for the 11th World Puzzle Championship). In this variant, the puzzle is to place five T-shaped pentominoes on the board, consistent with the row and column tallies. Another example can be found in the archives of the Russian puzzle site "KIG" (December 2006, No. 52, page 9).  Here is the original puzzle and the original PDF file.
Path Battleships	From the USA/Canada/Finland Team Qualifying Test (for the 11th World Puzzle Championship). This variant is identical to Classic (Standard) Battleships, with the additional proviso that all of the remaining cells not used by the fleet can be traversed by a single, closed loop (connecting cells horizontally or vertically).
"Magnets": a Battleship-like puzzle	This Battleship-like puzzle from the 10th World Puzzle Championship, featured in the September 2002 issue of GAMES Magazine. Although not a Battleships variant per se, it has elements of shape placement and row / column tallies.
Level Battleships	First published in the 3rd PQRST Puzzle Championships, this is a variation of Black-and-White Battleships. In Level Battleships, there is one fleet (consisting of battleships, cruisers, and destroyers) above the water, and one fleet (consisting only of submarines) beneath the water.
Thermometer Battleships	In this variation, the ships are replaced with thermometers. Locate the ten thermometers in the grid so they don't touch each other, not even diagonally. There are one 4-unit thermometer, two 3-unit thermometers, three 2-unit thermometers, and four 1-unit thermometers. Either a thermometer is empty or some or all of its units are filled with mercury, but always starting from its head. Numbers on the right and bottom of the grid reveal the number of cells filled with mercury. An important note: as presented in the PQRST 02 quarterly and online puzzle competition, the thermometer puzzle has multiple solutions.
Moving Battleships (with tallies)	This Battleship-like puzzle from the 11th World Puzzle Championship, featured in the April 2003 issue of GAMES World of Puzzles. A fleet is located in one grid. The ships then simultaneously move exactly 3 units forward or backwards (sideways and diagonal moves are not allowed), resulting in a second grid. Determine the initial position of the ships in the first grid and second grids.
Moving Battleships (without tallies)	First appearing in the 11th PQRST Puzzle Championship, this variant is related to Moving Battleships (with tallies). As with many PQRST puzzles, Moving Battleships (without tallies) is harder to solve because of the large number of possible ship placements and the lack of tallies. Here's the authors' description: "Locate the 10-ship fleet into the grid so that they don’t touch each other, not even diagonally, and can then perform a simultaneous movement in which each ship moves three squares in a straight line at the same speed, resulting in a final position where again they don’t touch each other, not even diagonally. Each ship must move either forward or backward, but four submarines can move in any one of the four directions. Ships may touch each other during the movement, but there can not be two ships occupying the same square after a movement of a single unit while they are moving. Water marks are only considered for the starting position." Here is the original puzzle and its solution.
Six Packs	This Battleship-like puzzle from the 11th World Puzzle Championship, featured in the April 2003 issue of GAMES World of Puzzles. Although not a Battleships variant per se, it has elements of shape placement and row / column tallies similar to Hexagonal Battleships.
Bigrid Battleships	First published in the 6th PQRST Puzzle Championship. A standard Battleships fleet is divided between two 6x6 boards.
Cylindrical Battleships	Similar to Wraparound Battleships, the difference being that only the columns wrap around, not the rows. The original puzzle was featured on Marcelo Inglesias's blog "Acertijos y pequeños enigmas" (in Spanish) as "Batalla Naval VI".
Wraparound Battleships	This intriguing variation appeared in the June 2003 issue of GAMES Word of Puzzles. Created by Battleships afficionado Dave Tuller, it is Standard Battleships with a twist: Each grid has the properties of a torus, that is, its left edge is connected to the right edge, and the top edge to the bottom. A ships may "wrap around" any edge of the board and occupy one or more squares at opposite ends of the same row or column. Click for the original puzzles and their solutions. Marcelo Inglesias's blog ("Acertijos y pequeños enigmas") in Spanish features a Wraparound Battleship puzzle (battleship puzzle VII).
Two-Story Battleships	Takahiko Saito created this variant on his puzzle site. Following the rules of Standard Battleships, some ships can have a second floor. The segments tallies on the side and bottom include any second-floor segments. Thanks to Otto Janko for pointing these out to me.  Be sure to visit Otto's excellent Battleship site.
Product Battleships	First published in the 8th PQRST Puzzle Championship: "Position the 10-ship fleet horizontally or vertically into the grid. Ships can not touch each other, not even diagonally. Numbers on the sides are the product of the digits on the occupied cells in the respective row or column. If there is only one occupied cell in a row or column, the digit on it is written on the side." Here is the original puzzle and its solution.
Tank Search	First published in the 8th PQRST Puzzle Championship: "There are three tanks hiding in the grid. Each tank is made of seven cells and tanks don't touch each other not even diagonally. Numbers tell the total number of tank cells in their row and column. Find the locations of the tanks." Here is the original puzzle and its solution. Note: the original puzzle has three (3) possible solutions.
Height Battleships	First published in the 7th PQRST Puzzle Championship: "Position the 10-ship fleet horizontally or vertially into the grid. Ship kinds have different height as written on them. The numbers on the sides of the grid tell the number of ships seen in that row or column from that direction." Here is the original puzzle and its solution.
Optimum Battleships	First published in the 7th PQRST Puzzle Championship: "There are three tanks hiding in the grid. Each tank is made of seven cells and tanks don't touch each other not even diagonally. Numbers tell the total number of tank cells in their row and column. Find the locations of the tanks." Here is the original puzzle, the best solution, and a list of all solutions (both correct and incorrect) submitted. Cihan Altay, the mastermind behind the PQRST web site, is the author of the puzzle, and Scott Sheehan is to be congratulated for writing an excellent puzzle grader/solution finder.
Numbers by Numbers	Created by Cihan Altay (the force behind the PQRST puzzle site) for the 2003 Google U.S. Puzzle Championship: "Solve this puzzle as you would a regular Paint by Numbers puzzle (the numbers above and to the left of the grid indicate how many groups of black squares there are in the corresponding row or column, and in order, how many consecutive black squares there are in each group." Here is the original puzzle and its solution.
Arithmetic Battleships	Submitted by Alberto Fabris for the 2004 Puzzle Design Tournament: "In the 10x10 grid below, every cell corresponds to a couple of digits, one to the left of the row and one on the top of the column. Every segment of the ships represents a single operation. Locate the whole fleet into the grid and calculate every single score between the two digits and the symbol for the occupied cells. Ships can not touch each other, not even diagonally. For every operation the first number is the greater, the second is the smaller, and the result is calculated up to the second decimal digit. Maximize your total result." Here is the original puzzle and the best solution submitted.
Sea Battle ("vlootoefening" in Dutch)	Created by Paul van Leeuwen for the 12th World Puzzle Championship in Arnhem, The Netherlands: "Four countries (A, B, C, and D) each have their own Battleship fleet at sea. They have some ships in the own region, and some in the central neutral zone, marked by the dotted lines. There is exactly one complete fleet in the neutral zone. No ships are allowed in squares crossed by the dotted line. All ships are oriented either horizontally or vertically, and they do not touch one another, not even diagonally. The wavy lines indicate open ocean (i.e., unoccupied squares); The numbers outside the grid reveal the total number of ship segments that appear in each respective row or column." Here is the original puzzle and its solution. On 21 May 2009 Paul posted information related to this puzzle in Conceptis's puzzle forums (here's a link).  Paul also provided a JPEG of the same puzzle.
Japanese Battleships	I chanced upon this interesting Battleship variant found on the site of the Russian puzzle site "Diogen". Created by Andrei Bogdanov, here is the puzzle description: "Place the set of battleships-5 (1 five-tube, 2 four-tube, 3 three-tube, 4 two-tube and 5 one-tube ships) in the grid. Ships cannot touch it other, not even diagonally. Digits above and at left show (in order) the size of blocks of "sea" cells in corresponding row." Here is the original puzzle and its solution.
Chess Battleships (a min-max puzzle)	This minimum-maximum puzzle originated on the Diogen puzzle web site.  Here's their description: "On a chess board you have to locate chess pieces so that a full standard fleet of 10 ships can be placed into the non-attacked cells. The ships can not touch each other, not even diagonally. All other cells (other than the ones that pieces are on) of the board must be attacked at least by one chess piece. The chess pieces can not attack each other. You have unlimited quantity of knights (N), bishops (B), rooks (R), queens (Q) and kings (K). Find a board with a) minimum b) maximum quantity of chess pieces." Here is the original puzzle and its solution.
Rhombus Battleships	Found on the Diogen puzzle web site, this variation requires placing non-standard "ships" on the board (in this case a hexagonal board). Note that the light blue line of cells in the diagram should be ignored (it was meant as an aid for sending in the solution). Here is the original puzzle and its solution.
Unknown Battleships	First published in the 12th PQRST Puzzle Championship: "Place numbers 1, 2, 3, 6, 7, 8 once each into the six empty boxes near the grid. Then locate the 10-ship fleet into the grid so that they don’t touch each other, not even diagonally. Numbers on the sides tell the number of ship segments seen in that row or column. There are no ship segments on squares with a water mark." Here is the original puzzle and its solution. Here is a reference to this puzzle on a Japanese blog (click here for English translation).
Russian Battleship	Featured on the Diogen puzzle web site, as part of the first-round 2005 puzzle tournament.  The description is as follows: Place the complete set of ships into the 10x10 grid.  Ships cannot touch each other, not even diagonally.  Each number in the grid shows the distance (horizontally or vertically) from the center of that numbered cell to the center of some ship's cell (if the ship has an even number of segments it there can be two center cells).  There is exactly one ship whose center is at this distance.  Ships cannot occupy a numbered cell.  It is possible that a particular ship's center cell is not pointed to by any number, and a ship's center cell may be pointed to by more than one number. Here is the original puzzle and its solution.
Aiming Battleships	Another Battleship variant featured on the Diogen puzzle web site, as part of the second-round 2005 puzzle tournament.  The description is as follows: "Put standard fleet into the grid. Ships cannot touch each other even diagonally. Arrow on the ship shows the line of sighting. Every ship takes to aim at nearest (in arrow direction) ship and is taking to aim by other. Digits at right and bottom show the numbers of ship's cells in corresponding row." Here is the original puzzle and its solution.
Triple-Fleet Battleships	A Battleship variant featured on the Diogen puzzle web site, as part of the first-round 2004 puzzle tournament.  The description is as follows: "Put 15 ships (5 ships in every colour: red, green, blue) on the field. Each ship occupies three cells and may be horizontal, vertical or diagonal. Ships with same colour cannot touch each other even diagonally. Numbers outside the field shows how many cells of ships with given colour are in corresponding column (raw)." Here is the original puzzle and its solution.
Battleship Observers	A Battleship variant featured on the Diogen puzzle web site, as part of the second-round 2004 puzzle tournament.  The description is as follows: "Place the set of battleships (tubes must be on the gridlines intersection, and ships must follow lines) so that quantity of tubes visible by three observers will be minimal. Ships cannot intersect each other. Ships cannot be in point with observer. In example the observer X sees 3 tubes." Here is the original puzzle and its solution.
Boarding Battleships	A Battleship variant featured on the Diogen puzzle web site, as part of the fourth-round 2004 puzzle tournament.  The description is as follows: "Place two fleets (trade and pirate's) at the battle field. Every fleet has one four-tubes ships, two three-tubes, three two-tubes and four one-tubes. All ships cannot touch the other ship of the same fleet. Every pirates' ship boards (touch by exactly one cell) one trade ship having same size. Pirates' ships can also touch other trade ships, but without battle. Crosses mark the cells of trade ships which boarding by pirates. Numbers at the bottom and rights denote overall quantity of cells occupied by ships in corresponding column or row." Here is the original puzzle and its solution.
Shuffled Battleships	Another original Battleship variant featured on the Diogen puzzle web site, as part of the third-round 2005 puzzle tournament.  The description is as follows: "The standard fleet (1 four-tube, 2 three-tube, 3 two-tube and 4 one-tube ships) is placed into the grid. Ships cannot touch each other, not even diagonally. A spy satellite took six partial photos of the fleet, but they were shuffled. Locate the positions of all the ships in the grid. All photos except A may be rotated but not reflected. Photo A oriented correctly. Two cells without ships are already marked." Here is the original puzzle and its solution.
Halves Battleships	A Battleship variant featured on the Diogen puzzle web site (called "Placing" on the site), as part of the third-round 2005 puzzle tournament.  The description is as follows: "Place the six given figures (looking like letters) into the grid so that they do not touch each other, not even diagonally. Numbers below and to the right of the grid show the area occupied by the figures in each corresponding row or column. Figures can be rotated but not reflected." Here is the original puzzle and its solution.
Laser Battleships	A Battleship variant featured on the Diogen puzzle web site as part of the fourth-round 2005 puzzle tournament.  The description is as follows: "Place the six given figures (looking like letters) into the grid so that they do not touch each other, not even diagonally. Numbers below and to the right of the grid show the area occupied by the figures in each corresponding row or column. Figures can be rotated but not reflected." Here is the original puzzle and its solution.
PQRST Letters	First published in the 13th PQRST Puzzle Championship.  The description is: "Locate all of the p, q, r, s, t letter figures into the grid once each without overlapping each other. You may rotate the figures, but can not reflect them. Numbers at the top and left tell the number of figures seen in that row or column; whereas numbers at the bottom and right tell the number of occupied cells in that row or column." Here is the original puzzle and its solution.
Single-Fleet Subset Battleships	First published on Marcelo Inglesias's puzzle blog site "Acertijos y pequeños enigmas" (Battleship puzzle XIV).  This variant is a standard Battleship puzzle with one caveat: only a subset of a standard fleet is used.  In other words, one or more ships of the standard fleet are missing.  The object, as always, is to identify the location of the ships. Marcelo writes that he invented this variant to prevent using the common strategy of quickly placing the battleship.
Double-Fleet Subset Battleships	First published on Marcelo Inglesias's puzzle blog site "Acertijos y pequeños enigmas" (Battleship puzzle XV).  This variant is similar to the Single-Fleet Subset variant (i.e., a standard grid contains only a subset of a standard fleet).  In this variant, however, the fleet used is a subset of two standard fleets. So, for example,. the number of submarines will be 0 to 8, there may be from 0 to 2 battleships, etc.
Two-Ocean Battleships	First published on Marcelo Inglesias's puzzle blog site "Acertijos y pequeños enigmas" (Battleship puzzle XVI).  Here's a rough translation from Marcelo's site: "There are two adjacent grids, one above the other. In each board a complete fleet has hidden. The numbers to the right indicate the amount of occupied squares in the respective row. The numbers in the central row indicate the occupied sum of the square in the adjacent columns of each board." Here is a copy of the original puzzle.
Sudoku Battleship	This variant featured in the 2nd World Sudoku Championship in Prague (28 March - 1 April 2007).  The instruction booklet has great descriptions of a large number of Sudoku variations.
Battleships TetraDoku (by Raymond Young)	Here's the description from GAMES Magazine (April 2011): "This new puzzle combines battleships, tetraminoes, and sudoku.  Place the seven ships given below each grid into the grid such that: (1) No two ships touch, even diagonally; (2) The total of the numbers in the squares of the ship(s) occupying each row or column equals the number given to the right of or above that row or column; and (3) The numbers obey sudoku logic -- that is, no digit repeats in any row, column, or 3x3 box.  After you place the ships in each grid, solve the remaining sudoku puzzle." Here are the original puzzles and their solutions.