The S-61N I flew on the North Sea never had a fuel dump facility. However 1 aircraft (G-ATBJ) operated offshore in India from Juhu, was fitted with dumping from the centre tank to allow a reasonable payload to be carried in the high temps experienced there.
For the same reason all the anti-ice equipment was removed, including the heated windscreens, which became a problem in the monsoon when the screens misted up!