diff --git a/src/lib/commands/mfir.c b/src/lib/commands/mfir.c
index e02f61b8..432f71d8 100644
--- a/src/lib/commands/mfir.c
+++ b/src/lib/commands/mfir.c
@@ -810,7 +810,7 @@ quiet_bigdef(int attacker, struct emp_qelem *list, natid own, natid aown,
 	    range = mapdist(ship.shp_x, ship.shp_y, ax, ay);
 	    if (range > erange)
 		continue;
-	    if (!line_of_sight((s_char **)0, ship.shp_x, ship.shp_y, ax, ay))
+	    if (!line_of_sight(NULL, ship.shp_x, ship.shp_y, ax, ay))
 		continue;
 
 	    (*nfiring)++;
diff --git a/src/lib/commands/sona.c b/src/lib/commands/sona.c
index 50730ddf..d08c59d7 100644
--- a/src/lib/commands/sona.c
+++ b/src/lib/commands/sona.c
@@ -51,7 +51,7 @@
 #include "commands.h"
 #include "optlist.h"
 
-static int blankrow(s_char *);
+static int blankrow(char *);
 
 int
 sona(void)
@@ -74,37 +74,37 @@ sona(void)
     int changed = 0;
     int row;
     /* Where these are used are non-re-entrant, so we keep 'em around */
-    static s_char **rad = (s_char **)0;
-    static s_char *radbuf = (s_char *)0;
-    static s_char **vis = (s_char **)0;
-    static s_char *visbuf = (s_char *)0;
+    static char **rad = NULL;
+    static char *radbuf = NULL;
+    static char **vis = NULL;
+    static char *visbuf = NULL;
 
     if (!snxtitem(&ni, EF_SHIP, player->argp[1]))
 	return RET_SYN;
     if (!radbuf)
-	radbuf = malloc((WORLD_Y * (WORLD_X + 1)) * sizeof(s_char));
+	radbuf = malloc((WORLD_Y * (WORLD_X + 1)));
     if (!visbuf)
-	visbuf = malloc((WORLD_Y * (WORLD_X + 1)) * sizeof(s_char));
+	visbuf = malloc((WORLD_Y * (WORLD_X + 1)));
     if (!rad) {
-	rad = malloc(WORLD_Y * sizeof(s_char *));
+	rad = malloc(WORLD_Y);
 	if (rad && radbuf) {
 	    for (x = 0; x < WORLD_Y; x++) {
 		rad[x] = &radbuf[(WORLD_X + 1) * x];
 	    }
 	} else if (rad) {
 	    free(rad);
-	    rad = (s_char **)0;
+	    rad = NULL;
 	}
     }
     if (!vis) {
-	vis = malloc(WORLD_Y * sizeof(s_char *));
+	vis = malloc(WORLD_Y);
 	if (vis && visbuf) {
 	    for (x = 0; x < WORLD_Y; x++) {
 		vis[x] = &visbuf[(WORLD_X + 1) * x];
 	    }
 	} else if (vis) {
 	    free(vis);
-	    vis = (s_char **)0;
+	    vis = NULL;
 	}
     }
     if (!radbuf || !visbuf || !rad || !vis) {
@@ -128,7 +128,7 @@ sona(void)
 	   xyas(ship.shp_x, ship.shp_y, player->cnum),
 	   ship.shp_effic, srange);
 	snxtsct_dist(&ns, ship.shp_x, ship.shp_y, srange);
-	blankfill((s_char *)radbuf, &ns.range, 1);
+	blankfill(radbuf, &ns.range, 1);
 	while (nxtsct(&ns, &sect)) {
 	    if (player->owner || sect.sct_type == SCT_WATER)
 		rad[ns.dy][ns.dx] = dchr[sect.sct_type].d_mnem;
@@ -385,7 +385,7 @@ line_of_sight(char **rad, int ax, int ay, int bx, int by)
 }
 
 static int
-blankrow(s_char *s)
+blankrow(char *s)
 {
     while (*s) {
 	if (*s != ' ')
diff --git a/src/lib/commands/torp.c b/src/lib/commands/torp.c
index 9ae9b2dd..1c4154d4 100644
--- a/src/lib/commands/torp.c
+++ b/src/lib/commands/torp.c
@@ -187,7 +187,7 @@ torp(void)
 	    pr("Hitchance = %d%%\n", (int)(hitchance * 100));
 	}
 	/* Now, can the torpedo even get there? */
-	if (!line_of_sight((s_char **)0, sub.shp_x, sub.shp_y,
+	if (!line_of_sight(NULL, sub.shp_x, sub.shp_y,
 			   vship.shp_x, vship.shp_y)) {
 	    pr("BOOM!... Torpedo slams into land before reaching target.\n");
 	    /* We only tell the victim if we were within range. */
@@ -272,8 +272,7 @@ anti_torp(int f, int ntorping, int vshipown)
 	if (range > erange)
 	    continue;
 
-	if (!line_of_sight((s_char **)0, sub.shp_x, sub.shp_y,
-			   dd.shp_x, dd.shp_y))
+	if (!line_of_sight(NULL, sub.shp_x, sub.shp_y, dd.shp_x, dd.shp_y))
 	    continue;
 
 	if (cantorp(&dd, &sub)) {
diff --git a/src/lib/subs/mission.c b/src/lib/subs/mission.c
index 960d31ea..de745048 100644
--- a/src/lib/subs/mission.c
+++ b/src/lib/subs/mission.c
@@ -571,7 +571,7 @@ perform_mission(coord x, coord y, natid victim, struct emp_qelem *list,
 		if (md > range)
 		    continue;
 
-		if (!line_of_sight((s_char **)0, x, y, gp->x, gp->y))
+		if (!line_of_sight(NULL, x, y, gp->x, gp->y))
 		    continue;
 		sp->shp_item[I_SHELL] = shell - SHP_TORP_SHELLS;
 		mobcost = sp->shp_effic * 0.01 * sp->shp_speed;