What is the absolute pressure in the ocean at 53 feet?

I found an old reference book and converted to modern units. 53 'feet' is 16.16 metres. Every 10 metres pressure increases by one atmosphere, so 16.16 metres equals 1.616 'extra' atmospheres, or, total 2.616 atmospheres at 16.16 metres. So...on any given day, to find the total pressure at your '53 feet', multiply local ambient pressure (in whatever units you prefer) by 2.616 to determine total (absolute) pressure at that depth. Don't ever forget, all naturally occurring pressures are dynamic; all pressures at all depths will be significantly higher on "good" weather days, than on "bad".
[(53/33)+1] = 2.61