" Corrosion ranks with fatigue
as the most common cause of material failure"
Handbook
of Marine Surveying - Thomas Ask
Corrosion is the nemesis of all mariners, one of natures phenomena is
the fact that two different connected metals immersed in electrolyte (in
our case sea water or polluted fresh water) develop electrical voltage
and current, the result of which is the loss of the most active metal
- your propeller, rudder, p bracket or other under water item.
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It seems that everything touching seawater quickly weakens due
to the unstoppable effects of corrosion. "Corrosion ranks with
fatigue as the most common cause of material failure" however
they often work together, what corrosion starts fatigue will finish.
Anodes are fitted and bonded onto your boat because they are designed
to readily give up their loosely attached electrons to other materials,
thus protecting your other immersed items.
With anodes undertaking such a vital role can you be certain that
your £20.00 anode is protecting your £5000.00 pair of
propellers?
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The answer is yes, there are several ways. One is to constantly
lift your boat to check the anodes are being eroded at the correct
rate.
However, this still leaves you with the uncertainty as to whether
the anode is over protecting, under protecting or is just right
for your cathodes (propellers, shafts, rudder etc).
Another option would be hiring a diver to check the anodes, but
that would only tell you their present state, giving you no indication
to their actual lifespan.
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Both of these options are costly and time consuming and still do not
give you the full picture on the status of your anodes.
The Landau UK Galvanic Survey
A preferable alternative would be to instruct Landau UK Ltd to carry out
a full Galvanic Survey. This would detail a report assessing the following
information:
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How well each under water
item is bonded and how effectively the anodes are protecting important
equipment. |
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Highlight any stray AC
or DC current problem from the dock or boats own system |
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Make recommendations
on galvanic systems on board and any improvements that can be made
to any part of it. |
Landau UK's Galvanic Survey is suitable for boats of all types and construction
and can be carried out while the boat is in the water. Addtionally our
service is cheaper than less adequate options, giving you a full report
and piece of mind.
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