Summary Fishing is one of the most dangerous occupations, as demonstrated by fatal accident statistics for the fishing industry compared with those for other occupations. Conditions are difficult on a fishing boat, with the work performed on a slippery, moving platform exposed to the weather. For greater safety and ease of execution of fishing operations, anti-roll systems are used to reduce the impact of the motion of the vessel. The main function of such systems is to limit lateral motion without too much impact on the longitudinal pitching motion caused by the sea. The purpose of this project was 1) to inventory anti-roll systems on midshore fishing vessels in operation in Québec and 2) to conduct comparative performance tests of the two most popular anti-roll systems used in Québec, folding fins (an emerging system) and paravanes (most widely used in our fleet). The inventory showed that half of the 292 vessels of more than 15 registered tons are equipped with paravane systems, whereas only 11% have folding-fin anti-roll systems. The use of folding fins is, however, on the rise. A complementary survey in October 2010 of 53% of vessel captain-owners who have equipped their boats with folding fins showed a high rate of satisfaction on all levels: ease of handling, comfort, safety and general performance at sea. In the summer of 2010, sea trials were conducted aboard twin crabbers, the Danie Martine, equipped with paravanes, and the Rudy L1, equipped with folding fins. The purpose of the trials was to find out if the Rudy L1 outperformed the Danie Martine with respect to three aspects of concern to fishermen and regulatory agencies: vessel stability, crew safety and comfort, and cost of energy (fuel). Sea trials were conducted over three days in the Baie-des-Chaleurs off the coast of the Gaspé peninsula. On each of these days, 21 trials lasting 15 minutes each were conducted during which the three major variables were tested: 1) position of the anti-roll system (vertical, semi-deployed and immersed); 2) vessel speed depending on operations (adrift, half-speed as during a fishing operation and full speed as when travelling between the dock and the fishery); 3) vessel position with respect to wind direction (headed into the wind, running with the wind or cross wind). Data were continuously recorded with specialized tools, including an inertial navigation system (INS), a torque indicator on the drive shaft, a GPS system for determining speed made good (SMG) and an anemometer for determining wind speed and direction. The weather was quite mild during the three days of testing, so the sea was not too rough. Given these conditions, average roll amplitude recorded during lateral motion of the Danie Martine and the Rudy L1 was within a safe range, between two and six degrees. However, the minimum average roll amplitude values were recorded on the Danie Martine and the maximum values on the Rudy L1—though the differences were small, especially when the anti-roll systems were immersed. Pitch amplitude was smaller when the vessels were adrift or running at half-speed and the anti-roll systems were not deployed. Minimum pitch amplitude was about 1.0 degrees and maximum about 2.5 degrees. Pitch amplitude of the Rudy L1 was greater than that of the Danie Martine when the vessels were travelling. In terms of energy consumption, the Rudy L1 proved more economical than the Danie Martine at half-speed, but energy consumption of the two vessels was similar at full speed and when the anti-roll systems were deployed. Like the paravanes, the folding fins reduce rolling and increase the general stability of the vessel and the safety of the crew. Our visual observations also indicated that the folding fins are simpler and easier for crew members to deploy than the paravanes. It is also easier for the captain to determine the span of the folding fins, whose geometry is fixed, whereas the geometry of the paravanes depends on the effect of water resistance on the paravane-cable coupling. In other words, with the folding fins it is easier to avoid obstacles floating on the surface or in the subsurface.