Index: src/lang/english.txt
===================================================================
--- src/lang/english.txt	(revision 27203)
+++ src/lang/english.txt	(working copy)
@@ -1252,8 +1252,8 @@
 STR_CONFIG_SETTING_PLANE_CRASHES_NORMAL                         :Normal
 STR_CONFIG_SETTING_STOP_ON_TOWN_ROAD                            :Allow drive-through road stops on town owned roads: {STRING2}
 STR_CONFIG_SETTING_STOP_ON_TOWN_ROAD_HELPTEXT                   :Allow construction of drive-through road stops on town-owned roads
-STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD                      :Allow drive-through road stops on roads owned by competitors: {STRING2}
-STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD_HELPTEXT             :Allow construction of drive-through road stops on roads owned by other companies
+STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD                      :Allow certain constructions on roads/canals owned by competitors: {STRING2}
+STR_CONFIG_SETTING_STOP_ON_COMPETITOR_ROAD_HELPTEXT             :Allow construction of drive-through road stops on roads owned by other companies, and construction of locks on canals owned by other companies.
 STR_CONFIG_SETTING_DYNAMIC_ENGINES_EXISTING_VEHICLES            :{WHITE}Changing this setting is not possible when there are vehicles
 STR_CONFIG_SETTING_INFRASTRUCTURE_MAINTENANCE                   :Infrastructure maintenance: {STRING2}
 STR_CONFIG_SETTING_INFRASTRUCTURE_MAINTENANCE_HELPTEXT          :When enabled, infrastructure causes maintenance costs. The cost grows over-proportional with the network size, thus affecting bigger companies more than smaller ones
Index: src/water_cmd.cpp
===================================================================
--- src/water_cmd.cpp	(revision 27203)
+++ src/water_cmd.cpp	(working copy)
@@ -265,6 +265,16 @@
 	/* lower tile */
 	WaterClass wc_lower = IsWaterTile(tile - delta) ? GetWaterClass(tile - delta) : WATER_CLASS_CANAL;
 
+	if (!_settings_game.construction.road_stop_on_competitor_road && HasTileWaterClass(tile - delta) && GetWaterClass(tile - delta) == WATER_CLASS_CANAL) { // Skip if it's not canal
+		if (!IsTileType(tile - delta, MP_INDUSTRY)) {
+			Owner o_lower = GetTileOwner(tile - delta);
+			if (o_lower != OWNER_NONE) { // Skip if canal owner is none
+				ret = CheckTileOwnership(tile - delta);
+				if (ret.Failed()) return ret;
+			}
+		}
+	}
+
 	if (!IsWaterTile(tile - delta)) {
 		ret = DoCommand(tile - delta, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 		if (ret.Failed()) return ret;
@@ -278,6 +288,16 @@
 	/* upper tile */
 	WaterClass wc_upper = IsWaterTile(tile + delta) ? GetWaterClass(tile + delta) : WATER_CLASS_CANAL;
 
+	if (!_settings_game.construction.road_stop_on_competitor_road && HasTileWaterClass(tile + delta) && GetWaterClass(tile + delta) == WATER_CLASS_CANAL) { // Skip if it's not canal
+		if (!IsTileType(tile + delta, MP_INDUSTRY)) {
+			Owner o_upper = GetTileOwner(tile + delta);
+			if (o_upper != OWNER_NONE) { // Skip if canal owner is none
+				ret = CheckTileOwnership(tile + delta);
+				if (ret.Failed()) return ret;
+			}
+		}
+	}
+
 	if (!IsWaterTile(tile + delta)) {
 		ret = DoCommand(tile + delta, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 		if (ret.Failed()) return ret;