Captain William Bligh was  invited to survey Dublin Bay by the director general of  inland navigation.  He had a reputation, earned in the South Seas, as a marine surveyor. He arrived in Dublin in September 1800 and commenced work immediately.  He completed his survey and report in 3 months, noting in his report that this had been achieved notwithstanding the unfavourable and tempestuous time of the year.

Bligh's complete report and chart are now in the records of the Dublin Port and Docks board.  His proposal was a wall on the North side of the channel, parallel with the South wall, to speed the flow of water and to assist the natural scour. This proposal was accepted in principle.  As a result of further investigation it was decided to build the present Bull Wall at an angle to Clontarf's foreshore, thereby enclosing a greater volume of water between the two walls and consequently increasing the scouring effect of the ebb tide.