Riva 122-foot Mythos motoryacht Currently under construction at the CRN yard, the Riva 122-foot long 'Mythos' is Riva's largest motoryacht built yet. The all-aluminium planing motoryacht has a design by Mauro Micheli of Officina Italiana Design. A pair of MTU 12V 4000 M93L engines are responsible for Mythos' anticipated top speed of 27-knots. The 37-meter aluminium yacht will come complete with a square jacuzzi on the flybridge as well as ample sun-bathing areas. Guests will be able to sun on pads located either on the bow, just aft of the jacuzzi as well as on the aft decks.