A “dead fish swim” is a swim that even a dead fish could finish. (Maybe not literally… but sometimes almost literally.)
This is a bit of local (SF) open-water swimming lingo that I wish would be more widely used (hence this post).
Dead fish swims require bodies of water affected by substantial currents - as fast or faster than “fast” swimmers swim. Let’s set the minimum current threshold for a dead fish swim (arbitrarily) at 2 knots.
Most of the organized swims put on by the Dolphin and South End Rowing Clubs in San Francisco Bay are dead fish swims. Coghlan Beach to Aquatic Park on a flood (the traditional route for the fall Inter-Club Triathlon) is a dead fish swim. Pier 7 to Aquatic Park (the most popular SERC “sunriser” route) on a big ebb is a dead fish swim.
Even the challenging Bay to Breakers swim is sort of a dead fish swim - until the last mile or so, when the current goes slack and you have to get around Seal Rocks and into the beach via actual swimming (and bodysurfing).
Non-dead fish swims include cross-current swims such as the traditional 1.25-mile Alcatraz-to-Aquatic Park swim; and perhaps the premier test of open-water swimming skill and navigational IQ in the Bay - the Round-Trip Alcatraz (Aquatic Park to Alcatraz, around Alcatraz, then back to Aquatic Park).
Dead fish swims are an enjoyable way to see a relatively long stretch of city skyline in a relatively short amount of time - without having to do much actual swimming. Logistically, they are an effective way to keep fast swimmers and slow swimmers closer together than they would be in slack water.
Dead fish swims may give inexperienced Bay swimmers a false sense of their skills. Ability to bob along in a ripping current does not imply ability to swim long distances.
Dead fish swims are fun. So is swimming against the current - but for different reasons.
Of course, with the Chas Lap, you get the best of both worlds.