diff --git a/include/sect.h b/include/sect.h
index 6e64ce39..f5d6722e 100644
--- a/include/sect.h
+++ b/include/sect.h
@@ -187,6 +187,13 @@ extern struct dchrstr dchr[SCT_TYPE_MAX + 2];
     (opt_RAILWAYS ? sct_rail_track((sp)) != 0			\
      : intrchr[INT_RAIL].in_enable && (sp)->sct_rail != 0)
 
+#define SCT_MINES_ARE_SEAMINES(sp) \
+    ((sp)->sct_type == SCT_WATER || (sp)->sct_type == SCT_BSPAN)
+#define SCT_SEAMINES(sp) \
+    (SCT_MINES_ARE_SEAMINES((sp)) ? (sp)->sct_mines : 0)
+#define SCT_LANDMINES(sp) \
+    (SCT_MINES_ARE_SEAMINES((sp)) ? 0 : (sp)->sct_mines)
+
 #define MOB_MOVE    0
 #define MOB_MARCH   1
 #define MOB_RAIL    2
diff --git a/src/lib/commands/mine.c b/src/lib/commands/mine.c
index 06933379..99dc5753 100644
--- a/src/lib/commands/mine.c
+++ b/src/lib/commands/mine.c
@@ -68,7 +68,7 @@ mine(void)
 	    continue;
 	mines_avail = MIN(shells, mines);
 	if (getsect(ship.shp_x, ship.shp_y, &sect) == 0 ||
-	    (sect.sct_type != SCT_WATER && sect.sct_type != SCT_BSPAN)) {
+	    !SCT_MINES_ARE_SEAMINES(&sect)) {
 	    pr("You can't lay mines there!!\n");
 	    continue;
 	}
@@ -117,7 +117,7 @@ landmine(void)
 	    continue;
 	}
 	if (!getsect(land.lnd_x, land.lnd_y, &sect)
-	    || sect.sct_type == SCT_WATER || sect.sct_type == SCT_BSPAN
+	    || SCT_MINES_ARE_SEAMINES(&sect)
 	    || sect.sct_own != land.lnd_own) {
 	    pr("You can't lay mines there!!\n");
 	    continue;
diff --git a/src/lib/commands/stre.c b/src/lib/commands/stre.c
index f6552522..1215c31f 100644
--- a/src/lib/commands/stre.c
+++ b/src/lib/commands/stre.c
@@ -88,11 +88,11 @@ stre(void)
 	def->own = 0;
 	eff = att_combat_eff(def);
 	if (sect.sct_own == sect.sct_oldown || player->god) {
-	    if (sect.sct_mines > 0)
+	    if (SCT_LANDMINES(&sect) > 0) {
 		pr("%7d", sect.sct_mines);
-	    else
+		eff *= (1.0 + MIN(sect.sct_mines, 20) * 0.02);
+	    } else
 		pr("%7s", "");
-	    eff *= (1.0 + MIN(sect.sct_mines, 20) * 0.02);
 	} else {
 	    pr("%7s", "?");
 	}
diff --git a/src/lib/subs/attsub.c b/src/lib/subs/attsub.c
index 95349c51..a5abbbe6 100644
--- a/src/lib/subs/attsub.c
+++ b/src/lib/subs/attsub.c
@@ -1656,7 +1656,8 @@ get_mine_dsupport(struct combat *def, int a_engineer)
     getsect(def->x, def->y, &sect);
 
     if (sect.sct_oldown != player->cnum) {
-	mines = MIN(sect.sct_mines, 20);
+	mines = SCT_LANDMINES(&sect);
+	mines = MIN(mines, 20);
 	if (a_engineer)
 	    mines = ldround(mines / 2.0, 1);
 	if (mines > 0) {
diff --git a/src/lib/subs/bridgefall.c b/src/lib/subs/bridgefall.c
index 40086a18..fe408880 100644
--- a/src/lib/subs/bridgefall.c
+++ b/src/lib/subs/bridgefall.c
@@ -132,6 +132,8 @@ knockdown(struct sctstr *sp)
 	"Crumble... SCREEEECH!  Splash! Bridge%s falls at %s!\n",
 	sp->sct_type == SCT_BTOWER ? " tower" : "",
 	xyas(sp->sct_x, sp->sct_y, sp->sct_own));
+    if (!SCT_MINES_ARE_SEAMINES(sp))
+	sp->sct_mines = 0;
     sp->sct_type = SCT_WATER;
     sp->sct_newtype = SCT_WATER;
     sp->sct_own = 0;
diff --git a/src/lib/subs/lndsub.c b/src/lib/subs/lndsub.c
index bfda69e5..03b8de0d 100644
--- a/src/lib/subs/lndsub.c
+++ b/src/lib/subs/lndsub.c
@@ -553,10 +553,10 @@ lnd_sweep(struct emp_qelem *land_list, int verbose, int takemob,
 		    prland(&llp->unit.land));
 	    continue;
 	}
-	if (sect.sct_type == SCT_BSPAN) {
+	if (SCT_MINES_ARE_SEAMINES(&sect)) {
 	    if (verbose)
-		mpr(actor, "%s is on a bridge.  No mines there!\n",
-		    prland(&llp->unit.land));
+		mpr(actor, "%s is in a %s sector.  No landmines there!\n",
+		    prland(&llp->unit.land), dchr[sect.sct_type].d_name);
 	    continue;
 	}
 	if (takemob) {
@@ -620,9 +620,7 @@ lnd_check_mines(struct emp_qelem *land_list)
 	getsect(llp->unit.land.lnd_x, llp->unit.land.lnd_y, &sect);
 	if (sect.sct_oldown == llp->unit.land.lnd_own)
 	    continue;
-	if (sect.sct_type == SCT_BSPAN)
-	    continue;
-	if (!sect.sct_mines)
+	if (SCT_LANDMINES(&sect) == 0)
 	    continue;
 	if (chance(DMINE_LHITCHANCE(sect.sct_mines) / (1 + 2 * with_eng))) {
 	    lnd_hit_mine(&llp->unit.land, ((struct lchrstr *)llp->chrp));
diff --git a/src/lib/subs/move.c b/src/lib/subs/move.c
index 34fe0c92..91a8931f 100644
--- a/src/lib/subs/move.c
+++ b/src/lib/subs/move.c
@@ -318,7 +318,7 @@ check_lmines(coord x, coord y, double weight)
     int dam = 0;
 
     getsect(x, y, &sect);
-    if (sect.sct_mines > 0 &&
+    if (SCT_LANDMINES(&sect) > 0 &&
 	sect.sct_oldown != player->cnum &&
 	chance(DMINE_LHITCHANCE(sect.sct_mines)) && chance(weight / 100.0)) {
 	pr_beep();
diff --git a/src/lib/subs/plnsub.c b/src/lib/subs/plnsub.c
index b13a7e0e..9bae8323 100644
--- a/src/lib/subs/plnsub.c
+++ b/src/lib/subs/plnsub.c
@@ -904,7 +904,7 @@ plane_sweep(struct emp_qelem *plane_list, coord x, coord y)
     if (mines_there == 0)
 	return;
 
-    if ((sect.sct_type != SCT_WATER) && (sect.sct_type != SCT_HARBR))
+    if (sect.sct_type != SCT_WATER)
 	return;
 
     for (qp = plane_list->q_forw; ((qp != plane_list) && (mines_there));
diff --git a/src/lib/subs/retreat.c b/src/lib/subs/retreat.c
index 64acb854..79283024 100644
--- a/src/lib/subs/retreat.c
+++ b/src/lib/subs/retreat.c
@@ -475,7 +475,7 @@ retreat_land1(struct lndstr *lp, char code, int orig)
 	if (stopping)
 	    continue;
 
-	mines = sect.sct_mines;
+	mines = SCT_LANDMINES(&sect);
 	if ((lcp->l_flags & L_ENGINEER) && mines > 0 &&
 	    (sect.sct_oldown != lp->lnd_own)) {
 	    max = lcp->l_item[I_SHELL];