What Can Be Done to Prevent Corrosion?

The selection of materials is of prime importance in the construction of craft. Generally naval architects and boat builders ensure that they select metals which are as far as possible compatible to each other and when this is not possible metals must be isolated from one another. There will always be occasions when fittings or steel-work require replacement or repair and it is important that when this is done attention is paid to the same criteria. In particular ensure that fastenings and split pins are compatible and of the highest quality. The paint system on any boat is an important first barrier against corrosion. Seek advice from the paint manufacturers for their recommendations on the most appropriate coating system and follow the application instructions completely. Ensure that a good anti-corrosive primer is applied if anti fouling is to be used. When using a copper based anti-fouling none of the paint must be applied directly to bare metal surfaces.
Vegetable oil based paints, although far less widely available than in the past, should not be used with cathodic protection systems as the paint tends to saponify.
The correct installation of electrics on a boat will reduce the possibility
of stray current leakage and the following actions are recommended:

• Use only high grade insulated wiring of suitable capacity. Undersized wires will cause resistance and consequent voltage drop.
• Clip or support all wires at suitable intervals to prevent fatigue and eventual fracture.
• Use only corrosion resistant terminals and connectors and make sure that all are clean and tight.
• Attach only the main battery leads to battery terminals.
• Fit an isolation switch in the battery circuit.
• Ensure that all battery circuits are correctly fused.
• Keep all wiring, connections and junction boxes above the bilge area and other areas likely to become wet.
• Make sure that when fitting additional equipment the work is carried out in accordance with the manufacturer’s instructions. The polarity of connections should be correct and each circuit must be correctly fused.
• Electrical and Electronic work is best carried out by a qualified marine electrician.

Ongoing maintenance on your boat is essential. Metal work, paint coatings and electrical installations all require regular inspection.
In particular you should inspect the wind and water line area if owning a steel vessel. This area is particularly vulnerable because it is often prone to mechanical damage but derives no protection from an anode system being above the water line.