Line setters are used with integrated weight (IW) (50 g m^–1 lead core) longlines by some autoline vessels in the Kerguelen and Crozet Islands Patagonian toothfish (Dissostichus eleginoides) fisheries to deter seabirds, ostensibly by expediting gear sink rates. A trial was conducted in the Ross Sea to determine the effectiveness of line setters in increasing the sink rates of IW longlines. Time-depth recorders were deployed on lines set with and without a line setter using a paired-treatment design. Sink rates of longlines set with and without a line setter were identical, including in the first few metres of the water column where seabird interactions are likely to be most intense. Longlines deployed with the line setter entered the water several metres closer to the stern of the vessel and commenced sinking sooner, thus increasing slightly (<0.5 m) the depth of longlines for given distances astern. This increase in depth is minor and unlikely to result in substantial reductions in interactions between longlines and seabirds in the Kerguelen and Crozet fisheries.