diff --git a/OpenRa.Game/Combat.cs b/OpenRa.Game/Combat.cs
index 69bb75fd54..33365a4fc0 100644
--- a/OpenRa.Game/Combat.cs
+++ b/OpenRa.Game/Combat.cs
@@ -4,6 +4,7 @@ using System.Linq;
 using System.Text;
 using OpenRa.Game.GameRules;
 using OpenRa.Game.Effects;
+using OpenRa.Game.Traits;
 
 namespace OpenRa.Game
 {
@@ -50,5 +51,14 @@ namespace OpenRa.Game
 
 			return rawDamage * multiplier;
 		}
+
+		public static bool WeaponValidForTarget(WeaponInfo weapon, Actor target)
+		{
+			var projectile = Rules.ProjectileInfo[weapon.Projectile];
+
+			if (projectile.ASW) return false;	// we don't support ASW yet. change this when subs can be identified.
+			if (projectile.AA && target.traits.Contains<Helicopter>()) return true;
+			return projectile.AG;
+		}
 	}
 }
diff --git a/OpenRa.Game/GameRules/ProjectileInfo.cs b/OpenRa.Game/GameRules/ProjectileInfo.cs
index db21594967..97352b6f9d 100644
--- a/OpenRa.Game/GameRules/ProjectileInfo.cs
+++ b/OpenRa.Game/GameRules/ProjectileInfo.cs
@@ -4,7 +4,7 @@ namespace OpenRa.Game.GameRules
 	class ProjectileInfo
 	{
 		public readonly bool AA = false;
-		public readonly bool AG = false;
+		public readonly bool AG = true;
 		public readonly bool ASW = false;
 		public readonly bool Animates = false;
 		public readonly bool Arcing = false;
diff --git a/OpenRa.Game/Traits/AttackBase.cs b/OpenRa.Game/Traits/AttackBase.cs
index d679c3f480..c14d2768ea 100644
--- a/OpenRa.Game/Traits/AttackBase.cs
+++ b/OpenRa.Game/Traits/AttackBase.cs
@@ -63,6 +63,8 @@ namespace OpenRa.Game.Traits
 			var weapon = Rules.WeaponInfo[weaponName];
 			if (weapon.Range * weapon.Range < (target.Location - self.Location).LengthSquared) return false;
 
+			if (!Combat.WeaponValidForTarget(weapon, target)) return false;
+
 			fireDelay = weapon.ROF;
 			var projectile = Rules.ProjectileInfo[weapon.Projectile];
 
diff --git a/units.ini b/units.ini
index ca963a9373..01a51517f8 100755
--- a/units.ini
+++ b/units.ini
@@ -117,7 +117,8 @@ Traits=Unit, Mobile, RenderUnit
 Description=Gunboat
 WaterBound=yes
 BuiltAt=syrd
-Traits=Unit, Mobile, RenderUnit
+Traits=Unit, Mobile, Turreted, AttackTurreted, RenderUnitTurreted
+PrimaryOffset=0,-6,0,-1