diff --git a/src/kernel/build.c b/src/kernel/build.c
index 29dfc81f0..d9e1cc8bc 100644
--- a/src/kernel/build.c
+++ b/src/kernel/build.c
@@ -239,7 +239,7 @@ int destroy_cmd(unit * u, struct order *ord)
         }
         else {
             /* partial destroy */
-            sh->size -= (sh->type->construction->maxsize * n) / 100;
+            sh->size -= (ship_maxsize(sh) * n) / 100;
             ADDMSG(&u->faction->msgs, msg_message("shipdestroy_partial",
                 "unit region ship", u, r, sh));
         }