...the closed end upright while keeping the open end submerged would you still have 40 feet of water in the standpipe? I ask this question because I have patented a pump that uses an inverted standpipe and I would like to know if it will work past 33 feet
All the air in the world has weight. A column of air one inch square and all the way to the sky weighs close 14.7 pounds. Most of the time. So if you have a perfect vacuum in your pipe, the weight of air will support a column of water weighing 14.7 pounds, and that is close to 30 feet.
Salt water is heavier, so a column of salt water might be as low as 27 feet depending on the amount of salt. Air bubbles in the water make it lighter so it can go much higher than 30 feet. A coffee percolator uses steam to make the water lighter so it is raised far above the water in the pot.