You can either save your map, export it, and then open up Worldcraft again and go to the toolbar MAP, and Load Pointfile... It will create a red zig-zaggy line all over your 2d views.
Or, (The better way), make sure to save and export your map and then play it in CS. Yes, it will be laggy as hell. Then go to console and type 'pointfile.' That way you will be able to see the linein 3d, since Worldcraft doesn't let you see your pointfile in 3d view for some ungodly reason.
Follow that line! It will lead outside to where the crack in the hull is. Only problem is if you have multiple cracks... Oh well.