alert bay boats defence defence-forces naval navy on-duty patrol patrol-boats patrolling readiness ready seaside secure security vessel vessels Anzac Day contemplation defence forces loss memorial reflection remembrance sadness soldiers war ADF air air-industry air-travel angles Australian-Defence-Forces blades exercises flight flying flyover formation height helicopter helicopters high manoeuvres military military-flyover perspectives rotors sky speed transport transportation travel traveling travelling ANZAC-Day ANZAC-memorial Australia peace Perth reminder symbol symbolic war-memorial Western-Australia memories slogan eternal-flame flame acknowledgement appearance historic historical history lest-we-forget light marble marble-memorial metal smooth stonework torch torches tribute