Derek the structures on the bow are for docking a Stevpris / Danforth type anchor- much larger than the normal Hall ship mooring anchor. One would be deployed at each 'corner' of the ship to hold her in position while the crane was working. Nowadays its done with bow and stern thrusters and dynamic positioning via gps satellite. I remember working on a model of the Stena Seawell back in the mid 80's that had the same set up. The ship would be moored on station and the four winches would work together to keep the ship on station.
The way it works is, imagine a X your mooring position is in the centre. You manouvre to top right, drop the stb bow anchor, pay out the cable and manouvre sternwards to lower right, drop the stb stern anchor, pay out cable. Do the same for the other two legs and then manouvre back to centre, paying out or taking up cable on the winches as necessary. Once over your 'spot' all the winches tension the cables to hold you there.
As you will by now have realised, the time taken to achieve this could be the best part of a day. Arrive on station and hold yourself there with thrusters and dynamic positioning is so much faster- time is money!