AN underwater rock mound will be constructed in the north-western corner of the Fremantle’s inner harbour to protect the rail bridge from being hit by boats.

Fremantle Ports says the decision to install the barrier follows shipping incidents in 2011 and 2014.

The mound will provide additional protection for the north western section of the bridge. The remaining sections are already protected by the Wongara Shoal and by structures installed in front of some of the bridge pylons by the Public Transport Authority.

The mound will be clearly marked by navigational aids and is  about 60 metres long and 20 metres wide.  The highest point will be visible only in some low tidal conditions.

The port says it won’t get in the way of any vessels.