Suppose, that in a particular area of the ocean on an earth-like planet, all water molecules are transmuted into an exotic variety of $H_2O$ that is identical to normal water in every way except with a boiling point 95 degrees C lower than ordinary water at any given level of pressure (i.e. a graph like this would be shifted down 95 on the Y axis). Any normal water entering the area is also transmuted, and any exotic water that leaves reverts to normal
Let's assume that the affected area is a cylinder 100km in diameter, extending from the ocean floor 3.5km below sea level (the average ocean depth on earth) to the edge of space. Assume further that it is located in a stretch of open ocean at a latitude similar to, say, San Diego (where average surface temps are above 15C or so year-round).
What would area of ocean look like once it reached equilibrium?
For certain living creatures at or near the surface would die instantly as their blood boils.
Water on the surface would immediately boil away, but it quickly gets complicated deeper down. Atmospheric pressure increases by about 1 atmosphere for every 10 meters of ocean depth, so initially the exotic water below 10-20 meters would remain liquid at normal ocean temps, but then the pressure would decrease as the top layers boil off. At the same time, normal water would be flowing in from outside, but would also boil rapidly. There are probably other effects still that I'm not considering. Probably as fairly-cold water vapor drifts out into the normal region you'd also have a considerable amount of rain or fog along the perimeter.
I've described above the general factors at play, what I can't figure out is how these balance out. What would this area look like from the perspective of a ship crossing into the area?