MGDUFF is the UK’s original marine cathodic protection company. In the early 1950’s Merlin Graham “Chunky” Duff, partnered by naval architects and marine engineers developed and set the standards for ship and small craft corrosion protection. Sixty years on these are still the accepted principles and our continuous development builds on that heritage, ^ keeping pace with modern vessel M Sacrificial anodes in zinc, aluminium and magnesium are manufactured at our foundries here in the , specifications and using the highest purity ingredients. MGDUFF products are specified and fitted by leading European yacht and boat builders, commercial shipping companies and ship repair yards. Experienced personnel offer customers cathodic protection schemes, full technical back-up and produce anode designs for ships, tugs, ferries, and superyachts. FOUNDRY MGDUFF’s main foundry and warehouse, located at our south coast head office in Chichester, has the flexibility to meet short lead time requirements on bespoke anodes whilst maintaining excellent stock levels on standard items. All anodes are manufactured to strict quality standards through an ISO 9001 Quality Management System, and in particular our zinc anodes meet the stringent US MN-A-18001K specification code. Each melt is batch tested using our in-house spectrometer to check chemical composition. This ensures the correct percentage of alloying materials has been added, producing only a top quality anode.

CORROSION WILL OCCUR IN ALL TYPES OF WATER WITH DRAMATIC EFFECT Metals of differing electrochemical potential when in contact with one another form Galvanic cells. The metal with a lower potential in the galvanic cell will be anodic and will corrode. The same effect can occur in areas of different electrochemical potential in a single piece of metal such as a steel plate. Any craft moored and operating in fresh, salt or estuarine water is at risk from corrosion and the effects can be costly. Corrosion on Steel & Aluminium vessels can be identified as either areas of localised pitting to the hull...

For Type A, B or C Vessels the following anode selection table applies FOR EACH PROPELLER ASSEMBLY FIT ONE To determine the number and size of anodes required, match the type of vessel and select the anode suitable for the size of propeller and the type of water ■ TYPE A Vessels are single screwed with a very short length of propeller shaft exposed to the water and fitted with GRP or wooden rudders. One anode will be required to protect the propeller and shaft In Salt Water Propeller Diameter 250mm All schemes must be inspected annually and the anodes renewed if more than 50% wasted ZD56 Zinc...

FITTING AND BONDING SACRIFICIAL ANODES WHEN FITTING ANODES TO WOODEN OR GRP HULLED VESSELS REMEMBER: • The anode should be positioned on the outside of the hull below the waterline. • The anodes can “see” the parts to be protected. • The fixing studs are located above the bilges. • The anode location ensures the minimum run of bonding cable to the parts to be protected. • There must be reasonable internal access to the studs. • The anode should not be positioned forward of or in line with Echo Sounding Transducers or log Impellers. • Whenever an anode is fitted to a GRP or wooden hull an anode...

CATHODIC PROTECTION OF STEEL HULLED VESSELS For One Year in Salt or Brackish Water fit the following Aluminium Anodes WHEN DETERMINING THE CATHODIC PROTECTION REQUIREMENTS FOR A STEEL HULLED VESSEL THE FIRST CRITERION IS THE SURFACE AREA OF STEEL HULL BELOW THE WATER LINE - THE WETTED SURFACE AREA. This is calculated by multiplying the water line length by the sum of the beam and draft i.e. LWL x (Beam+Draft). This calculation will apply to most motor cruisers and sailing boats. Once the wetted surface area is calculated, it can be applied to the selection tables below from which the number of...

All anode weights shown are nominal Images are representative.All anode weights shown are nominal Images are representative. 11

IVfrDIIFFBolt On Anodes MGDUFF bolt on hull anodes have a variety of stud centres and hole diameters to suit all European and American designed boats. Bolt on anodes are a quick and effective way to secure anodes to your vessel, without the need for any specialist tools. MGDuff have a full range of fixing solutions to suit your vessel, please see page 18 & 19 for more information. MD77 EURO Magnesium Anode All anode weights shown are nominal Images are representative.All anode weights shown are nominal Images are representative. 13

SALT WATER Arneson Surface Drive Anodes Overall Dimensions (mm) MGDUFF offer two sizes of Arneson teardrop anodes as a direct replacement for the OEM anodes supplied with the drive. SALT WATER SALT WATER Zinc Strip Anodes (ZD42) N/A This is a low profile zinc anode with a non reactive aluminium insert, ideally suited for fitting to high speed vessels. Maximum length is 72” (1828mm), available cut to suit with a verity of different hole centres or via standard configurations detailed below. SALT WATER All anode weights shown are nominal Images are representative. Overall Dimensions (mm) All anode...

Weld On Anodes Weld on anodes are recommended on vessels where a long life anode scheme is fitted or where the anodes may be subject to considerable abrasion, vibration or other physical disturbance. For guaranteed continuity and a 100% secure fixing, a welded connection is best. All MGDuff zinc anodes are supplied with a cast-in steel core bars. A guide for anode selection can be found on page 8 & 9 of the catalogue. FRESHWATER MD20LP Magnesium Anode 2.0 KG SALT WATER SALT WATER Anode Body Dimensions All anode weights shown are nominal Images are representative.All anode weights shown are nominal...

Anode Fixing StudsAnode Backing Sheets MGDUFF anode fixing studs (MlOB & M16B range plus Stainless Steel) feature a fully welded square plate mounting washer, which is more secure than some designs with a simple threaded washer. Anode studs are a one time fitment and as a through hull fitting, the best available should be used. Often anodes are secured incorrectly, the anode core bar should be secured and not the anode material to the structure! A backing pad is designed to stop the back of the anode from wasting away, and possibly causes the anode fixing to come loose. It also provides a barrier...