Tissot has solid ties with racing. Swiss driver Loris Kessel wore a Navigator chronograph in the 1970s and was officially sponsored by Tissot in the 1976 Formula 1 Grand Prix. The brand is once again working with Kessel Racing, this time with Ronnie Kessel (son of Loris) to launch the limited edition Heritage 1973. The watch has been updated a bit with contemporary touches but maintains many retro elements that made the original Navigator such a compelling piece. A larger case, updated dial and sapphire crystal mark the major differences, and while not technically a reissue, it's a nice throwback to the 1973 classic. Let's take a closer look.The 316L stainless steel case has a satin-brushed finish with polished bevels – typical of the era – with a diameter of 43mm and height of 14.8mm. The cushion case is nearly identical in shape to the smaller 39mm Navigator with a slightly larger crown and pushers. A domed sapphire crystal replaces the Navigator's acrylic and a mineral glass exhibition caseback displays a decorated automatic movement. The case is water-resistant to 100 metres. Ad - Scroll to continue with article The dial adds a third sub-dial at 3 o'clock and pushes the Navigator's date window to 4:30. The black sub-dials on the silvery white dial maintain the panda aesthetic of the original and orange hands on the 12-hour and 30-minute sub-dials (at 6 and 3 o'clock) harken back to the Navigator's colour scheme, along with orange on the central chronograph hand. A black tachymeter spans the outer edge of both the new and old models, and the overall look of the Tissot Heritage 1973 closely matches the Navigator, despite the many differences. The hour and minute hands have green Super-LumiNova inserts, along with the hour markers.Powering the Tissot Heritage 1973 is an ETA (Valjoux) 7753 with 27 jewels, 28,800vph (4Hz) and a 48-hour power reserve. The original Navigator used a Lemania caliber 1342. Functions include central hours, minutes and chronograph seconds, sub-dial seconds at 9 o'clock, 12-hour counter at 6 o'clock, 30-minute counter at 3 o'clock and date at 4:30. Viewed from the exhibition caseback, the movement is decorated with perlage and a gold (coloured) Tissot rotor. A rarely seen element of the ETA 7753 is a flush pusher at 10 o'clock to set the date (requiring a tool). The Tissot Heritage 1973 is fitted with a black calfskin rally strap with butterfly clasp (with safety pushers) that's similar to one patented by Tissot in the 1960s. The Heritage 1973 is limited to 1,973 pieces (honouring the original Navigator) and retails for USD 2,100 or EUR 1,990. It's available at Tissot's online store worldwide. More information can be found at Tissot's website.