The "bows" are the curved chassis tubes that run from the top of the boot to the cockpit. As such, the paintwork on the bows is quite vulnerable to damage - mainly from the harness buckles. Caterham sell a pair of carbon fibre sleeves that fit over the top of the bows in order to give some protection to this area. Fitting the bow protectors is straight forward and also gives a satisfying visual upgrade.
The first step is to drill out the existing rivets that hold the panel to the bows on the inside of the cockpit. This can be achieved without removing the seats from the car, but it might be necessary to move them forwards and backwards on the runners to gain access to all the rivets.
Drilling out the rivets
With the rivets removed, it's a good idea to give the internals of the bows a good squirt of Dinitrol or something similar. Rather than worrying about corrosion, this will prevent the rivet heads that have dropped into the chassis tube (as a result of the drilling) from rolling around inside the tube and making a rattling noise.
Next the press stud on the outside of the bow tube can be unscrewed and removed. The only tricky part of installing the bow protectors is drilling a hole in the correct place through the carbon fibre to align with the stud screw hole. To do this, I found that I could poke the drill bit through the nearest rivet hole on the cockpit side of the tube so that it came through the crud hole. Then, when the bow protector is dry fitted in the correct location, a hole in the exact position for the press stud can be drilled.
Removing the press stud; Finding a drill access point; Drilling the bow protector
After that, it's simply a case of drilling new rivet holes through the cockpit panel into the bow protector and fitting the new rivets. A new black press stud was used to replace the standard sliver one just tidy up the aesthetics.
New black press stud; riveting the bow protectors in place; end result.