DSS is a wing-based system that reduces heeling, improving performance under sail and comfort when navigating. 142 Canova from Baltic Yachts is the first non-racing maxi yacht to employ this technology
by Giulio Sabatelli
SOME WINGS ARE USED TO FLY, WHILE OTHER WINGS, OR RATHER ONE SINGLE WING, HELPS YOU STAY WELL ANCHORED IN THE WATER. The Dynamic Stability System (DSS) we saw recently on the Baltic 142 Canova has the opposite function of a traditional foil: instead of allowing the hull to fly on the water, it has been designed to reduce heeling and increase stability. The aim is to improve performance, not through flying but by trying to maintain a good position on the water.
DSS is a single side wing that provides a reserve of the righting moment by producing upwards lift on the leeward side, thereby counteracting the heeling produced by the sails.
It’s a well-known fact that reducing a yacht’s heeling helps to improve its performance under sail. Until recently, this was achieved by increasing the weight of the bulb or draught. Both of these solutions have their disadvantages, however: most obviously limiting access to the coast and some ports, due to the particularly deep centerboard, while an overly large bulb also has the clear drawback of increasing friction. Then water ballast was introduced, which has the advantage of being a dynamic solution – when needed, you add water, and therefore weight, to the overall ballast, and when you want to make it lighter, all you need to do is empty the tanks. The disadvantage here is the bulky tanks
The other advantage of DSS is the increased comfort – the boat both lists and pitches less.
themselves, which take up valuable space on board. This is not much of an issue for a racing boat, but for yachts designed for cruising, even at high speeds, it is never advisable to waste space that could be used in another way.
A similar discussion could be had for another method used to limit heeling: the canting keel. This is another dynamic solution and does not take up space like water ballast, but it does increase the technical characteristics of the keel, and therefore potentially makes any problems connected to it more serious.
The DSS system is very simple to manage. The wing automatically produces an upward thrust on the leeward side, counteracting the heeling produced by the sails. There is no need for fine-tuning or specific management.
DSS is the brainchild of designer Hugh Welbourn and sailor Gordon Kay and has its roots in research and applications started twenty years ago. They met when Kay was looking for someone to help him optimize the performance of the Baltic 81 Martela, designed especially for the 1989 Whitbread race. Since then, many maxi yachts and racing boats have been given Welbourn and Kay’s DSS treatment, most recently the Baltic Yachts 142 Canova. What sets this yacht’s system apart is that it was designed at the same time as the hull – in most other cases it has been retrofitted to existing boats.
The performance under sail improves both because the DSS reduces heeling and because it helps to lift the entire boat, reducing hydrodynamic resistance.
This time the DSS system was developed in partnership with Bruce Farr and Baltic Yachts, a collaborative effort that has increased the system’s advantages: for example, the 142 Canova’s sail plan was developed specifically with DSS in mind. The result is more than satisfactory, and other maxi sailing yachts are therefore likely to follow suit. It not only benefits performance – the 142 Canova can achieve a top speed of 30 knots – but comfort too: a more stable boat that lists less is also more comfortable to travel in.
(Dynamic Stability System, the wings of stability – Barchemagazine.com – Marzo 2021)
