Webgui: improve table summary generation

webgui/index.php

@@ -135,7 +135,10 @@ $sth = $pdo->query("SELECT vid, vesselname, model FROM vessel ORDER BY vid");
 $res = $sth->fetchAll();
 foreach ($res as $row) {
     echo '      <option value="', $row['vid'], '"', ($row['vid'] == $vid ? ' selected>' : '>');
-    echo $row['vesselname'], ' - ',  $row['model'];
+    echo $row['vesselname'];
+    if ($row['model']) {
+        echo ' - ',  $row['model'];
+    }
     echo "</option>\n";
 }
 ?>
@@ -154,7 +157,7 @@ echo '    <button type="submit" class="btn btn-secondary" name="submit[add]">',
 echo '<div class="row my-2">', "\n";
 echo '<div class="col-1"></div>', "\n";
 echo '<div class="col">';
-if ($vessel->shipyard) {
+if ($vessel->shipyard && $vessel->shipyard > 0) {
     if ($vessel->shipyard == -3) {
        echo _('Custom-build');
     } else {