Yup. Stall is a function of engine torque at the point of stall only. How much torque or HP above that point is irrelevent to the stall.
A jet boats max attainable RPM is where the HP curve crosses the impellers power absorption curve. Same as the torque convertor.
I have had many jet boats since I was 24.
TIMINATOR
If a torque converter stall is the same as "A jet boats max attainable RPM is where the HP curve crosses the impellers power absorption curve." Wouldn't be the engines hp at stall that matters ?