diff --git a/include/ship.h b/include/ship.h
index 42278132..99f945de 100644
--- a/include/ship.h
+++ b/include/ship.h
@@ -183,4 +183,6 @@ extern int m_visib(struct mchrstr *, int);
 extern int m_frnge(struct mchrstr *, int);
 extern int m_glim(struct mchrstr *, int);
 
+extern int shp_dchrg(struct shpstr *);
+
 #endif
diff --git a/info/Damage.t b/info/Damage.t
index ca2cc8f1..be509228 100644
--- a/info/Damage.t
+++ b/info/Damage.t
@@ -17,7 +17,7 @@ You can be shelled by a fort, artillery unit, ship, depth-charge, or torpedo:
        fort damage = guns * eff * (random(30) + 20) / 7
        unit damage = guns * eff * (5 + random(6))
        ship damage = guns * eff * (10 + random(6))
-      depth damage =    2 * eff * (10 + random(6))
+      depth damage =    3 * eff * (10 + random(6))
        torp damage = 40 + random(40) + random(40)
 Note that for forts, a maximum of 7 guns may be fired.
 
diff --git a/src/lib/commands/mfir.c b/src/lib/commands/mfir.c
index b4ff03b7..632847f3 100644
--- a/src/lib/commands/mfir.c
+++ b/src/lib/commands/mfir.c
@@ -308,21 +308,6 @@ multifire(void)
 		pr("Not enough military for firing crew.\n");
 		continue;
 	    }
-	    gun = fship.shp_item[I_GUN];
-	    gun = MIN(gun, fship.shp_glim);
-	    if (fship.shp_frnge == 0 || gun == 0) {
-		pr("Insufficient arms.\n");
-		continue;
-	    }
-	    shell = fship.shp_item[I_SHELL];
-	    if (shell < 2)
-		shell += supply_commod(fship.shp_own,
-				       fship.shp_x, fship.shp_y,
-				       I_SHELL, 2 - shell);
-	    if (shell <= 0) {
-		pr("Klick!     ...\n");
-		continue;
-	    }
 	    if (fship.shp_effic < 60) {
 		pr("Ship #%d is crippled (%d%%)\n",
 		   fshipno, fship.shp_effic);
@@ -331,26 +316,46 @@ multifire(void)
 	    range = effrange(fship.shp_frnge, fship.shp_tech);
 	    range2 = roundrange(range);
 	    pr("range is %d.00 (%.2f)\n", range2, range);
-	    if (target == targ_sub) {
-		if ((mchr[(int)fship.shp_type].m_flags & M_DCH) == 0) {
-		    /* Don't tell it's a sub */
-		    range2 = -1;
-		} else if (shell < 2) {
+	    if (target == targ_sub
+		&& (mchr[(int)fship.shp_type].m_flags & M_DCH)) {
+		dam = shp_dchrg(&fship);
+		putship(fship.shp_uid, &fship);
+		if (dam < 0) {
 		    pr("Not enough shells for depth charge!\n");
 		    continue;
 		}
+	    } else {
+		if (target == targ_sub)
+		    /* Don't tell it's a sub */
+		    range2 = -1;
+		gun = fship.shp_item[I_GUN];
+		gun = MIN(gun, fship.shp_glim);
+		if (fship.shp_frnge == 0 || gun == 0) {
+		    pr("Insufficient arms.\n");
+		    continue;
+		}
+		shell = fship.shp_item[I_SHELL];
+		shell += supply_commod(fship.shp_own,
+				       fship.shp_x, fship.shp_y,
+				       I_SHELL, 2 - shell);
+		if (shell <= 0) {
+		    pr("Klick!     ...\n");
+		    continue;
+		}
+		gun = MIN(gun, shell * 2);
+		gun = MIN(gun, mil / 2);
+		gun = MAX(gun, 1);
+		shots = gun;
+		guneff = seagun(fship.shp_effic, shots);
+		dam = (int)guneff;
+		shell -= ldround(shots / 2.0, 1);
+		fship.shp_item[I_SHELL] = shell;
+		putship(fship.shp_uid, &fship);
 	    }
-	    gun = MIN(gun, shell * 2);
-	    gun = MIN(gun, mil / 2);
-	    gun = MAX(gun, 1);
-	    shots = gun;
-	    guneff = seagun(fship.shp_effic, shots);
-	    dam = (int)guneff;
-	    shell -= ldround(shots / 2.0, 1);
-	    fship.shp_item[I_SHELL] = shell;
-	    if (opt_NOMOBCOST == 0)
+	    if (opt_NOMOBCOST == 0) {
 		fship.shp_mobil = MAX(fship.shp_mobil - 15, -100);
-	    putship(fship.shp_uid, &fship);
+		putship(fship.shp_uid, &fship);
+	    }
 	} else if (attacker == targ_unit) {
 	    if (fland.lnd_own != player->cnum) {
 		pr("Not your unit!\n");
diff --git a/src/lib/commands/torp.c b/src/lib/commands/torp.c
index efec0d8e..9a10dbf5 100644
--- a/src/lib/commands/torp.c
+++ b/src/lib/commands/torp.c
@@ -240,9 +240,6 @@ anti_torp(int f, int ntorping, int vshipown)
 	    continue;
 	if (dd.shp_own != vshipown)
 	    continue;
-	if (dd.shp_effic < 60)
-	    continue;
-
 	if (!canshoot(&dd, &sub))
 	    continue;
 
@@ -326,29 +323,29 @@ fire_dchrg(struct shpstr *sp, struct shpstr *targ, int ntargets)
     int gun;
     double guneff;
 
-    shells = sp->shp_item[I_SHELL];
-    gun = sp->shp_item[I_GUN];
-    gun = MIN(gun, sp->shp_glim);
-    gun = MIN(gun, sp->shp_item[I_MILIT] / 2);
-
-    shells += supply_commod(sp->shp_own, sp->shp_x, sp->shp_y,
-			    I_SHELL, (gun + 1) / 2 - shells);
-
-    gun = MIN(gun, shells * 2);
-    if (gun == 0)
-	return;
-
-    /* ok, all set.. now, we shoot */
-    shells -= ldround(gun / 2.0, 1);
-    sp->shp_item[I_SHELL] = shells;
-    putship(sp->shp_uid, sp);
-
-    guneff = seagun(sp->shp_effic, gun);
-    dam = (int)guneff;
-    if (ntargets > 2)
-	dam /= ntargets / 2;
-
     if ((mchr[(int)targ->shp_type].m_flags & M_SUB) == 0) {
+	shells = sp->shp_item[I_SHELL];
+	gun = sp->shp_item[I_GUN];
+	gun = MIN(gun, sp->shp_glim);
+	gun = MIN(gun, sp->shp_item[I_MILIT] / 2);
+
+	shells += supply_commod(sp->shp_own, sp->shp_x, sp->shp_y,
+				I_SHELL, (gun + 1) / 2 - shells);
+
+	gun = MIN(gun, shells * 2);
+	if (gun == 0)
+	    return;
+
+	/* ok, all set.. now, we shoot */
+	shells -= ldround(gun / 2.0, 1);
+	sp->shp_item[I_SHELL] = shells;
+	putship(sp->shp_uid, sp);
+
+	guneff = seagun(sp->shp_effic, gun);
+	dam = (int)guneff;
+	if (ntargets > 2)
+	    dam /= ntargets / 2;
+
 	pr_beep();
 	pr("Kaboom!!! Incoming shells!\n");
 	if (sp->shp_own != 0)
@@ -359,6 +356,13 @@ fire_dchrg(struct shpstr *sp, struct shpstr *targ, int ntargets)
 	shipdamage(targ, dam);
 	putship(targ->shp_uid, targ);
     } else {
+	dam = shp_dchrg(sp);
+	putship(sp->shp_uid, sp);
+	if (dam < 0)
+	    return;
+	if (ntargets > 2)
+	    dam /= ntargets / 2;
+
 	pr("\nCAPTAIN!  !!Depth charges!!...\n");
 	if (sp->shp_own != 0)
 	    wu(0, sp->shp_own,
diff --git a/src/lib/subs/landgun.c b/src/lib/subs/landgun.c
index 87e60cb4..bd66b7f6 100644
--- a/src/lib/subs/landgun.c
+++ b/src/lib/subs/landgun.c
@@ -101,6 +101,29 @@ fort_fire(struct sctstr *sp)
     return (int)fortgun(sp->sct_effic, guns);
 }
 
+/*
+ * Drop depth-charges from ship SP.
+ * Use ammo, resupply if necessary.
+ * Return damage if the ship drops depth-charges, else -1.
+ */
+int
+shp_dchrg(struct shpstr *sp)
+{
+    int shells;
+
+    if (sp->shp_effic < 60 || (mchr[sp->shp_type].m_flags & M_DCH) == 0)
+	return -1;
+    if (sp->shp_item[I_MILIT] == 0)
+	return -1;
+    shells = sp->shp_item[I_SHELL];
+    shells += supply_commod(sp->shp_own, sp->shp_x, sp->shp_y,
+                           I_SHELL, 2 - shells);
+    if (shells < 2)
+       return -1;
+    sp->shp_item[I_SHELL] = shells - 2;
+    return (int)seagun(sp->shp_effic, 3);
+}
+
 /*
  * Return effective firing range for range factor RNG at tech TLEV.
  */
diff --git a/src/lib/subs/mission.c b/src/lib/subs/mission.c
index aaf00c61..1d82a552 100644
--- a/src/lib/subs/mission.c
+++ b/src/lib/subs/mission.c
@@ -569,19 +569,28 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 		range = roundrange(effrange(sp->shp_frnge, sp->shp_tech));
 		if (md > range)
 		    continue;
-		gun = sp->shp_item[I_GUN];
-		gun = MIN(gun, sp->shp_glim);
-		shell = sp->shp_item[I_SHELL];
-		if (shell < gun)
-		    shell += supply_commod(sp->shp_own,
-					   sp->shp_x, sp->shp_y, I_SHELL,
-					   gun - shell);
-		gun = MIN(gun, shell);
-		gun = MIN(gun, sp->shp_item[I_MILIT] / 2.0);
-		if (gun == 0)
-		    continue;
-		gun = MAX(gun, 1);
-		dam2 = seagun(sp->shp_effic, gun);
+		if (mission == MI_SINTERDICT) {
+		    dam2 = shp_dchrg(sp);
+		    putship(sp->shp_uid, sp);
+		    if (dam2 < 0)
+			continue;
+		} else {
+		    gun = sp->shp_item[I_GUN];
+		    gun = MIN(gun, sp->shp_glim);
+		    shell = sp->shp_item[I_SHELL];
+		    if (shell < gun)
+			shell += supply_commod(sp->shp_own,
+					       sp->shp_x, sp->shp_y, I_SHELL,
+					       gun - shell);
+		    gun = MIN(gun, shell);
+		    gun = MIN(gun, sp->shp_item[I_MILIT] / 2.0);
+		    if (gun == 0)
+			continue;
+		    gun = MAX(gun, 1);
+		    dam2 = seagun(sp->shp_effic, gun);
+		    sp->shp_item[I_SHELL] = shell - gun;
+		    putship(sp->shp_uid, sp);
+		}
 		if (range == 0.0)
 		    prb = 1.0;
 		else
@@ -600,9 +609,6 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 
 		mpr(victim, "%s %s fires at you at %s\n",
 		    cname(sp->shp_own), prship(sp), xyas(x, y, victim));
-
-		sp->shp_item[I_SHELL] = shell - gun;
-		putship(sp->shp_uid, sp);
 	    }
 	} else if (glp->thing->ef_type == EF_PLANE) {
 	    pcp = glp->cp;