The Portuguese Yacht Club Chronograph reference IW3905-04 is the second watch IWC has made in collaboration with Swiss boatbuilder Boesch - the first being the 2008 IWC Aquatimer Chronograph. The limited edition (150 pieces) Portuguese Yacht Club Chronograph Boesch features a mahogany-colored dial and a mahogany inlay on its case back, inspired by the Boesch 620 Bimini.