Why are tables not taught in OW classes anymore?

I ran across this article that frankly shocked me until I read it. See the "Dive Planning" link below, second page.


Shipwreck Essex
Type:
shipwreck, steamer
Built:
1890, Cramp Shipbuilding, Philadelphia PA USA
Specs:
( 272 x 40 ft ) 3018 tons
Sunk:
Thursday September 25, 1941
ran aground on Block Island - no casualties
Depth:
30 ft

bow, boilers, hull plates & ribs