JRC JLN-900 Installation And Instruction Manual page 51

2. Weld the Bottom Flange into the hole, ensure that it is positioned so that the Sea Valve
may be fitted inboard (in desired direction) without obstruction.
Welding Bottom Flange in Ship's Hull
The welded joint must be ground smooth and flush with the hull. There must be no
sharp edges to interfere with the water flow around the Transducer.
Welded joint grinding
4-13