diff --git a/mods/ra/rules/ships.yaml b/mods/ra/rules/ships.yaml
index f9670f5df9..de28cd8d1e 100644
--- a/mods/ra/rules/ships.yaml
+++ b/mods/ra/rules/ships.yaml
@@ -51,6 +51,7 @@ SS:
 	AttackFrontal:
 	AutoTargetPriority@DEFAULT:
 		ValidTargets: WaterActor, Underwater
+		InvalidTargets: NoAutoTarget, Structure
 	AutoTargetPriority@ATTACKANYTHING:
 		ValidTargets: WaterActor, Underwater
 	DetectCloaked: