The Adriatic Sea, situated between the Italian and Balkan peninsulas, has been a crucial intersection of diverse cultures, trade routes, and naval powers throughout history. The traditional boats of Adriatic seafaring have always used the wind as their main propulsion method. The sail equipment of these boats had a natural evolution over time, a process that came to an abrupt halt with the advent of motor propulsion.
The most iconic and traditional sail used throughout the Upper Adriatic is the vela al terzo (literally: "sail to the third"), a peculiar kind of lug sail, trapezoidal in shape and stretched by means of an upper and a lower pennone (yard). The name vela al terzo comes from the size of the portion of the sail that is in front of the mast, which is one-third the size of the portion behind the mast.
The Vela al Terzo is the result of centuries of evolution and refinement. beginning in the late 1500s and early 1600s. Before that time, the most common sail in the Adriatic was the medieval Latin sail, either in its triangular form, which was most common, or in the form with a cut front end, typical of the Central Mediterranean.
At the same time, inland only rarely on the sea, the tall and narrow rectangular sail, typical of the Pre-Alpine Lakes and some rivers of the Po Valley, was used. This kind of sail is extremely old, and it originated perhaps in Roman times, and we know that it was widely used in the early Middle Ages: it was very simple, only ideal for sailing with a tailwind. But it could also be angled by tying one sheet to the mast and pulling the other aft: it was, simplified, the same kind of rigging already in use in Roman times (pedem facere) in order to catch the wind from angled directions. This arrangement was later consolidated in new equipment and rigging such as the "lower yardarm" a "boom," the "drizza di penna," and the "botina".
The contact between the rectangular sail and the maritime Latin sail, led to an exchange of experiences from which the vela al terzo was born. The process probably took place around the beginning of the 1600s, at a time when the sails of the Renaissance tradition were beginning to undergo the changes suggested by oceanic navigation: the Latin Sail in some cases was replaced by the mainsail while the vela di civada, at the bow under the bowsprit, gave way to the more practical triangular polaccone.
In this framework there evolved variants and local adaptations of the rectangular Po Valley sail such as the vela al quarto, but as far as our Adriatic traditions are concerned, boats with a vela al terzo and a polaccone took over Venetian lagoon area. Towards the end of the 1600s, the vela al terzo quickly began to spread throughout the Adriatic, at first coexisting with the Latin sail. The result of this expansion was that, by the end of the 1800s, the vela al terzo was the only kind of sail used along the entire Western Coast of the Adriatic: from the Venetian Lagoon to Ancona and often as far as Dalmatia, Apulia, and Greece. When the trabaccolo became the most widespread medium-large boat in the Adriatic, the presence of the vela al terzo was consolidated and extended to other types of boats, such as the paranza, and the lancia (or lancetta).
It is this latter kind of vessel — slimmed down somewhat to be more nimble as a pure sailboat — that was used as the main template for the design of the DonMar, co-designed in 1969 by my uncle Carlo and Paquale Iurini, founder of the historical Jurini shipyard in Numana and master shipwright. While in the area of the Venice lagoon there still is a strong tradition of historical boats rigged with a vela al terzo, as of today the DonMar is the only such sailboat still active in the entire Marche region.