--- a/docs/landscape.html	Fri Dec 07 18:05:49 2007 +0000
+++ b/docs/landscape.html	Fri Dec 07 21:14:54 2007 +0000
@@ -945,6 +945,7 @@
        </tr>
       </table>
      </li>
+     <li>m4: Owner of the water</li>
      <li>m6 bits 7..6 : Possibility of a bridge above, in the <a href="#bridge_direction">direction specified</a></li>
      <li>m6 bits 1..0 : <a href="#tropic_zone">Tropic zone definition</a></li>
     </ul>

--- a/docs/landscape_grid.html	Fri Dec 07 18:05:49 2007 +0000
+++ b/docs/landscape_grid.html	Fri Dec 07 21:14:54 2007 +0000
@@ -194,8 +194,8 @@
       <td class="bits">XXXX XXXX</td>
       <td class="bits"><span class="free">OOOO OOOO OOOO OOOO</span></td>
       <td class="bits"><span class="free">OOOO OOOO</span></td>
-      <td class="bits"><span class="free">OOOO OOOO</span></td>
-      <td class="bits"><span class="free">OOOO OO</span>XX</td>
+      <td class="bits">XXXX XXXX</td>
+      <td class="bits">XXXX XXXX</td>
       <td class="bits">XX<span class="free">OO OO</span>XX</td>
       <td class="bits"><span class="free">OOOO OOOO</span></td>
     </tr>

--- a/src/openttd.cpp	Fri Dec 07 18:05:49 2007 +0000
+++ b/src/openttd.cpp	Fri Dec 07 21:14:54 2007 +0000
@@ -2203,6 +2203,20 @@
 		}
 	}
 
+	/*
+	 * Add the 'previous' owner to the ship depots so we can reset it with
+	 * the correct values when it gets destroyed. This prevents that
+	 * someone can remove canals owned by somebody else and it prevents
+	 * making floods using the removal of ship depots.
+	 */
+	if (CheckSavegameVersion(83)) {
+		for (TileIndex t = 0; t < map_size; t++) {
+			if (IsTileType(t, MP_WATER) && IsShipDepot(t)) {
+				_m[t].m4 = (TileHeight(t) == 0) ? OWNER_WATER : OWNER_NONE;
+			}
+		}
+	}
+
 	if (CheckSavegameVersion(74)) {
 		Station *st;
 		FOR_ALL_STATIONS(st) {

--- a/src/saveload.cpp	Fri Dec 07 18:05:49 2007 +0000
+++ b/src/saveload.cpp	Fri Dec 07 21:14:54 2007 +0000
@@ -29,7 +29,7 @@
 #include "strings.h"
 #include <list>
 
-extern const uint16 SAVEGAME_VERSION = 82;
+extern const uint16 SAVEGAME_VERSION = 83;
 uint16 _sl_version;       ///< the major savegame version identifier
 byte   _sl_minor_version; ///< the minor savegame version, DO NOT USE!
 

--- a/src/water_cmd.cpp	Fri Dec 07 18:05:49 2007 +0000
+++ b/src/water_cmd.cpp	Fri Dec 07 21:14:54 2007 +0000
@@ -81,8 +81,8 @@
 	for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) {
 		TileIndex neighbour = TileAddByDiagDir(t, dir);
 		if (IsTileType(neighbour, MP_WATER)) {
-			has_water |= IsSea(neighbour) || IsCoast(neighbour);
-			has_canal |= IsCanal(neighbour);
+			has_water |= IsSea(neighbour) || IsCoast(neighbour) || (IsShipDepot(neighbour) && GetShipDepotWaterOwner(neighbour) == OWNER_WATER);
+			has_canal |= IsCanal(neighbour) || (IsShipDepot(neighbour) && GetShipDepotWaterOwner(neighbour) != OWNER_WATER);
 		}
 	}
 	if (has_canal || !has_water) {
@@ -116,6 +116,8 @@
 
 	if (IsBridgeAbove(tile) || IsBridgeAbove(tile2)) return_cmd_error(STR_5007_MUST_DEMOLISH_BRIDGE_FIRST);
 
+	Owner o1 = GetTileOwner(tile);
+	Owner o2 = GetTileOwner(tile2);
 	ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 	if (CmdFailed(ret)) return CMD_ERROR;
 	ret = DoCommand(tile2, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
@@ -128,8 +130,8 @@
 	if (flags & DC_EXEC) {
 		depot->town_index = ClosestTownFromTile(tile, (uint)-1)->index;
 
-		MakeShipDepot(tile,  _current_player, DEPOT_NORTH, axis);
-		MakeShipDepot(tile2, _current_player, DEPOT_SOUTH, axis);
+		MakeShipDepot(tile,  _current_player, DEPOT_NORTH, axis, o1);
+		MakeShipDepot(tile2, _current_player, DEPOT_SOUTH, axis, o2);
 		MarkTileDirtyByTile(tile);
 		MarkTileDirtyByTile(tile2);
 		d_auto_delete.Detach();
@@ -138,6 +140,15 @@
 	return cost.AddCost(_price.build_ship_depot);
 }
 
+static void MakeWaterOrCanalDependingOnOwner(TileIndex tile, Owner o)
+{
+	if (o == OWNER_WATER) {
+		MakeWater(tile);
+	} else {
+		MakeCanal(tile, o);
+	}
+}
+
 static CommandCost RemoveShipDepot(TileIndex tile, uint32 flags)
 {
 	TileIndex tile2;
@@ -154,8 +165,8 @@
 		/* Kill the depot, which is registered at the northernmost tile. Use that one */
 		delete GetDepotByTile(tile2 < tile ? tile2 : tile);
 
-		MakeWater(tile);
-		MakeWater(tile2);
+		MakeWaterOrCanalDependingOnOwner(tile,  GetShipDepotWaterOwner(tile));
+		MakeWaterOrCanalDependingOnOwner(tile2, GetShipDepotWaterOwner(tile2));
 		MarkTileDirtyByTile(tile);
 		MarkTileDirtyByTile(tile2);
 	}

--- a/src/water_map.h	Fri Dec 07 18:05:49 2007 +0000
+++ b/src/water_map.h	Fri Dec 07 21:14:54 2007 +0000
@@ -85,6 +85,11 @@
 	return XYNSToDiagDir(GetShipDepotAxis(t), GB(_m[t].m5, 0, 1));
 }
 
+static inline Owner GetShipDepotWaterOwner(TileIndex t)
+{
+	return (Owner)_m[t].m4;
+}
+
 static inline DiagDirection GetLockDirection(TileIndex t)
 {
 	return (DiagDirection)GB(_m[t].m5, 0, 2);
@@ -128,13 +133,13 @@
 	_m[t].m5 = 0;
 }
 
-static inline void MakeShipDepot(TileIndex t, Owner o, DepotPart base, Axis a)
+static inline void MakeShipDepot(TileIndex t, Owner o, DepotPart base, Axis a, Owner original_owner)
 {
 	SetTileType(t, MP_WATER);
 	SetTileOwner(t, o);
 	_m[t].m2 = 0;
 	_m[t].m3 = 0;
-	_m[t].m4 = 0;
+	_m[t].m4 = original_owner;
 	_m[t].m5 = base + a * 2;
 }