History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c33.s1.t2.17

v1.c33.s1.t2.17

i) Stage I = It was designed to sluice ships 18-20 metres long and 4-6 metres wide. At least two ships could simultaneously pass and enter easily.
ii) Stage II = The inlet channel was too shallow and narrow to accommodate large ships and only flat bottoms could enter.