"engine order telegraph" . "Engine order telegraph" . "Chadburn telegraph" . . . "telegraph system" . . . "double slow bell" . "ship's telegraphs" . "ship's telegraph" . "wheelhouse telegraph" . . "repeating telegraphs" . "Engine order telegraph" . . "telegraph communication" . "Chadburn-type" . "telegraphed" . "telegraph" . "Chadburn" . "engine telegraph" .