Ardencaple Castle
...that Ardencaple Castle is used as a navigational aid for shipping on the Firth of Clyde?
...that <b id="mwEAQ"><a href="./Ardencaple_Castle" id="mwEAU" rel="mw:WikiLink" title="Ardencaple Castle">Ardencaple Castle</a></b> is used as a <a href="./Navigational_aid" id="mwEAY" rel="mw:WikiLink" title="Navigational aid">navigational aid</a> for shipping on the <a href="./Firth_of_Clyde" id="mwEAc" rel="mw:WikiLink" title="Firth of Clyde">Firth of Clyde</a>?