diff --git a/apps/openseachart/custom.html b/apps/openseachart/custom.html
index 64e1e76d8..2a96d311f 100644
--- a/apps/openseachart/custom.html
+++ b/apps/openseachart/custom.html
@@ -24,8 +24,8 @@
         z-index: 100;
       }
       #maptiles {
-        width: 896px;
-        height: 896px;
+        width: 448px;
+        height: 448px;
       }
     </style>
   </head>