Not too sure but looks like he did some longer marathon races in the 80s in difficult to pronounce parts of the world https://longswims.com/p/philip-rush/
Man, this guy has amazing recovery powers!!! I mean, over 4 straight weekends in July/August 1984 he did 4 OW swims averaging 32.8 km (20.4 mi) per swim, with an average time of about 8:48, or about 3.72 km/hr or 1:37/100m. Think about that…4 straight weekends of doing 20 mile swims. Hell, whenever I do a 6.2 mi (10K) swim, I feel like I need a week to recover. I think one single 20 mi swim would wipe me out for a month!!!
It would be interesting to know what this guy’s lifetime swim km is, gotta be huge!!!