Cathodics Flashcards
1
Q
What are the principles of cathodics?
A
2 dissimilar metals are in S/W & connected together,Current flows thru water, from anode to cathode.A basic galvanic cell.The Sacrifical anode dissolves while the cathode (hull) is stable.
2
Q
Dailies on cathodics
A
- carried out on amplifier assembley
- record current & voltage & ships speed
3
Q
Monthly on cathodics
A
- ship can be berthed but not beside other ship or stopped at sea
- Readings on hull potential using portable ref electrode 8 foot below waterline
4
Q
Principles of cathodics operation
A
- Maintain hull at negative potential using reference anode
- Voltage at -0.8 mv
- 2 voltages will make a signal and control current to hull anodes
5
Q
Over protection cathodics
A
- Blistering of hull paint & brittleness
6
Q
Under protection cathodics
A
No corrosion protection
