diff --git a/include/prototypes.h b/include/prototypes.h
index e241f6de..30679173 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -656,7 +656,7 @@ extern void show_news(int);
 /* shpsub.c */
 extern void shp_sel(struct nstr_item *, struct emp_qelem *);
 extern void shp_nav(struct emp_qelem *, double *, double *, int *, natid);
-extern int shp_sweep(struct emp_qelem *, int, natid);
+extern int shp_sweep(struct emp_qelem *, int, int, natid);
 extern char *shp_path(int, struct shpstr *, char *);
 extern void shp_put(struct emp_qelem *, natid);
 extern void shp_list(struct emp_qelem *);
diff --git a/src/lib/commands/navi.c b/src/lib/commands/navi.c
index 266f9733..793c3bd6 100644
--- a/src/lib/commands/navi.c
+++ b/src/lib/commands/navi.c
@@ -156,7 +156,7 @@ navi(void)
 	    } else if (cp[-1] == 'i') {
 		shp_list(&ship_list);
 	    } else {
-		stopping |= shp_sweep(&ship_list, 1, player->cnum);
+		stopping |= shp_sweep(&ship_list, 1, 0, player->cnum);
 	    }
 	    continue;
 	} else if (*cp == 'r' || *cp == 'l' || *cp == 's') {
diff --git a/src/lib/subs/shpsub.c b/src/lib/subs/shpsub.c
index 77f33d73..8cb234a4 100644
--- a/src/lib/subs/shpsub.c
+++ b/src/lib/subs/shpsub.c
@@ -210,7 +210,7 @@ shp_put(struct emp_qelem *list, natid actor)
 }
 
 int
-shp_sweep(struct emp_qelem *ship_list, int verbose, natid actor)
+shp_sweep(struct emp_qelem *ship_list, int verbose, int takemob, natid actor)
 {
     struct emp_qelem *qp;
     struct emp_qelem *next;
@@ -229,7 +229,7 @@ shp_sweep(struct emp_qelem *ship_list, int verbose, natid actor)
 		    prship(&mlp->ship));
 	    continue;
 	}
-	if (mlp->mobil <= 0.0) {
+	if (takemob && mlp->mobil <= 0.0) {
 	    if (verbose)
 		mpr(actor, "%s is out of mobility!\n", prship(&mlp->ship));
 	    continue;
@@ -241,8 +241,10 @@ shp_sweep(struct emp_qelem *ship_list, int verbose, natid actor)
 		    prship(&mlp->ship));
 	    continue;
 	}
-	mlp->mobil -= shp_mobcost(&mlp->ship);
-	mlp->ship.shp_mobil = (int)mlp->mobil;
+	if (takemob) {
+	    mlp->mobil -= shp_mobcost(&mlp->ship);
+	    mlp->ship.shp_mobil = (int)mlp->mobil;
+	}
 	putship(mlp->ship.shp_uid, &mlp->ship);
 	if (!(mines = sect.sct_mines))
 	    continue;
@@ -877,7 +879,7 @@ shp_nav_one_sector(struct emp_qelem *list, int dir, natid actor,
     }
     if (QEMPTY(list))
 	return stopping;
-    stopping |= shp_sweep(list, 0, actor);
+    stopping |= shp_sweep(list, 0, 0, actor);
     if (QEMPTY(list))
 	return stopping;
     stopping |= shp_check_mines(list);