Furuno FSV-24 - Manual (Page 12)

1-4
1.1.3 Remarks for installation of retraction tank
1. Make, if possible, the installation location a double bottom structure.
2. Install, if possible, the tank on the keel where the tank can be most firmly
fixed.
3. Install the reinforcement ribs as near as possible to the top of the retraction
tank, allowing space for tightening of bolts and nuts.
Retraction tank
250-300 mm
Reinforcement rib
How to install reinforcement ribs
4. Add a doubling plate at the location where the retraction tank is welded to the
hull bottom. The size of the doubling plate is normally 1300 mm in diameter
so that it may lie across two bottom frames.
5. Make the bow mark on the attachment flange with a chisel.