When fitting anodes to wooden or GRP hulled vessels remember: Hull Anode Installation

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1 When fitting anodes to wooden or GRP hulled vessels remember: The anode should be position 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. Hull Anode Installation Stiffen the inside of the hull where the anode is to be fitted if necessary. Drill holes to take the fixing studs at the appropriate centres. On wooden hulled vessels studs should be sleeved or painted to insulate them from the surrounding timber. When sleeving the stud either use a heat shrink tube or ensure that the inside of the sleeve is packed with a suitable marine grade sealant. Before inserting and securing each stud assembly, apply a generous amount of marine grade sealant to the shank and collar where the stud touches the hull to ensure a good seal. Whenever an anode is fitted to a GRP or wooden hull an anode backing sheet must be used to control the wastage of the anode and protect the hull. The anode backing sheet should be replaced each time the anode is replaced. Always ensure that the anodes are fitted with MGDUFF Fan Disc Washers under the securing nuts which will help to assure the contact between anode and cathodic protection system. The fan disc washers and nuts should be replaced each time the anode is replaced. Protect the anode fixing studs on assembly with paint or grease inside and outside the vessel. DO NOT PAINT THE WORKING SURFACE OF THE ANODE

2 Bonding the Cathodic Protection system The correct bonding of the cathodic protection system is imperative. Use 4mm2 PVC Insulated Multi-Stranded Copper Cable or larger. Ensure that all connections are clean and tight. The best way to bond the anode to the shaft is by using a MGDUFF Electro Eliminator as well as bonding the anode to the gear box or Engine casing. Insulated Flexible Couplings should be bridged by using a short length of bonding cable or a copper strap to carry through the contact between anode shaft and propeller. Bronze and Stainless Steel Rudders, Rudder Hangings and Shaft Brackets should also be bonded to the main anodes. Trim Tabs should be protected with separate anodes. Do not bond the same anode to ferrous and non-ferrous metals. Steel Rudders must be protected with separate anodes. Timber hulled vessels may be prone to electro-chemical decay and owners are recommended to contact MGDUFF for specialist advice or visit our website for more details. Fitting Instructions for Steel Hulled Vessels The main points to remember are: The anode should be position on the outside of the hull below the waterline under the turn of the bilge. ठʻ The anode should not be positioned forward of or in line with Echo Sounding Transducers or log Impellers.

3 Anodes may be welded or bolted to a steel hull NOTE: When fitting and replacing Bolt-On Anodes always ensure that the serrated fan disc washers are replaced. ठʻ DO NOT PAINT THE WORKING SURFACE OF THE ANODE To provide the best protection to the stern gear the shaft should be fitted with an MGDUFF Electro Eliminator Brush and earthed to the hull. Additionally the gearbox should be bonded to the hull using 4mm2 multi strand cable and any flexible couplings in the shaft should be bridged with a copper strap or cable.. The MGDUFF Electro-Eliminators offer the most effective shaft bonding solution. Running directly onto the propeller shaft the electro eliminator puts the anode on constant low resistance contact with the propeller shaft. The copper graphite brushes will give at least 2000 running hours under normal conditions. The electro eliminators will also remove the irritating interference to electronic equipment caused by the rotating shaft. Fitting Instructions for Aluminium Hulls NOTE: When fitting and replacing Bolt-On Anodes always ensure that the serrated fan disc washers are replaced.

4 To provide protection to the stern gear the shaft should be fitted with an MGDUFF Electro Eliminator Brush and earthed to the hull. Additionally the gearbox should be bonded to the hull using 4mm2 multi strand cable and any flexible couplings in the shaft should be bridged with a copper strap or cable. Anode Positioning 1. Position anodes around underwater hull as shown Below. Positions may be adapted slightly to suit individual vessels. 2. Prepare and paint the hull in accordance with a reputable paint manufacturers specification before anodes are fixed. 3. Fit anodes using galvanised mild steel set bolts with fan disc washer making sure that the anodes are pulled up tight against the hull. 4. No paint must be allowed to fall on the surface of the anode itself at any time. Maintenance To ensure correct level of protection anodes should be replaced when 80% consumed or if it is anticipated that they will be more than 80% consumed at the next scheduled docking. Ӂ Type ZD42 strip anodes This is a low profile zinc anode with a non reactive aluminium insert, ideally suited for fitting to high speed aluminium hulled vessels. The anode is not recessed but prominent on hull surface and can be attached after construction. Each anode requires 3 or more fixing positions:- ZD42/36" and ZD42/54" -3 fixing positions ZD42/72" -5 fixing positions (7 on fast craft). The ZD42 anode is supplied in 6ft (1830mm) lengths and may be cut to length. It can be supplied un-drilled or drilled and counter bored to standard centres, Fixing holes are drilled to suit 10mm studs and it is imperative that the fixing hole is counter bored down to the aluminium core. This shows a typical installation (suitable for attachment after construction).

5 This shows a typical installation (showing fitting arrangement for new buildings.) Hull mounted ZD55 Recessed Disc Anodes This 9" (225mm) diameter anode is generally utilised for flush mounting when minimum drag is required and is therefore normally incorporated on new construction where the circular recess can be arranged more easily Type ZD72B(M) Zinc Hull Anode This low profile cast anode is suitable for lower speed craft, where the surface ۉ仐 mounting will not result in excessive drag. It can be attached after construction. Fitting instructions for Ferrocrete vessels

6 (To be read in conjunction with the Anode Selection and Fitting Instructions for GRP Vessels) This type of construction requires some special consideration but in principal we recommend that vessels of this type are treated in the same way as a GRP hull but with regard to the following: As far as possible the hull steel reinforcement must be isolated from any metal work that is connected to the cathodic protection system. e.g. shaft brackets rudder bearings and glands as well as the anode itself. It is unlikely that the hull steel reinforcement can be completely isolated and it will put some demand on the sacrificial anode. It is important to select a big enough anode to provide sufficient protection for this. We recommend that when selecting the correct anode for your boat you refer to the Anode selection page for GRP Hulls in Salt Water and select the anode which is a size larger than that recommended for conventional GRP hulled vessels of the appropriate class. Mild Steel Rudders, Skegs and Bilge Keels should be protected using the ZD58 Zinc Disc Anode. When installing the anode on a ferrocrete hull ensure that: ەp (a) The anode fixing studs are isolated from the hull steel reinforcement by fitting a plastic insulating sleeve to the shank of the stud and applying a generous amount of marine grade sealant. (b) The Anode fixing stud collar should be bedded in several layers of Glass Fibre and Epoxy Resin. (c) The Anode should be fitted with a rubberised foam backing pad. (d) Always ensure that the anode is fastened with serrated washers under the fixing nuts to ensure a good connection. (e) The anode should be bonded in accordance with the instructions for a GRP hulled vessel as detailed in the above brochure.

7 Fitting Instructions for Copper Sheathed and Copper Clad Vessels. ( To be read in conjunction with the Anode Selection and Fitting Instructions for GRP Vessels ) The copper must be cut back to 20mm clear of the anode fixing studs collars. A pad of 6mm thick marine plywood is to be fitted between the rubberised anode backing sheet and the copper sheathing. The pad must be painted with an epoxy resin paint system or similar and is to be well bedded with marine grade sealant. The pad should extend at least 15mm clear of the anode and over the area where the copper has been cut back clear of the studs. ەp The copper must not be allowed to be in contact with any metal work which is being cathodically protected. The copper must be cut back from the outer end of the stern tube and any other metal fittings that are bonded into the cathodic protection system e.g. shaft brackets rudder bearings and glands if these are to be protected. It is advisable to check that the cathodic protection system is isolated from the copper using a suitable multi-meter. Where the copper has been cut back areas of exposed hull especially wooden hulls should be well painted with an appropriate epoxy resin paint system or similar. Metallic based anti-fouling must not be used on the plywood pad or on the areas where the copper has been cut back.

8 When selecting the correct anode for your boat please refer to the page for Cathodic Protection for GRP vessels in Salt Water and select the anode which is a size larger than that recommended for conventional GRP hulled vessel. Fitting Electro Eliminators Whether your boat is steel or GRP to provide the best protection to the stern gear the shaft should be fitted with an MGDUFF Electro Eliminator Brush. The MGDUFF Electro-Eliminators offer the most effective shaft bonding solution. Running directly onto the propeller shaft the electro eliminator puts the anode on constant low resistance contact with the propeller shaft. The copper graphite brushes will give at least 2000 running hours under normal conditions. The electro eliminators will also remove the irritating interference to electronic equipment caused by the rotating shaft. Electro Eliminator Number 1 for up to 2" diameter shafts (includes support bracket as shown) ەp Electro Eliminator Number 2 for 2" - 8" diameter shafts. (A support bracket must be fabricated to suit the installation of the unit, not supplied) Fitting Instructions for Shaft Anodes MGDUFF offer the widest range of shaft anodes in terms of type and size and material. It should be understood that this format of Cathodic protection although simple to fit affords a far lower degree of protection to the systems listed elsewhere on the website. In order to afford maximum protection the surface area of the anode must relate in ratio to that of the surfaces it is endeavouring to protect. A standard often impossible to achieve due to the products design. The fitting of more than one shaft anode can sometimes overcome this problem.

9 MGD - Super shaft anode, unlike the ZSA this shaft anode has a built in core bar which holds the anode firmly in place through the duration of its life. Available in Zinc & Aluminium ZSA - Standard shaft anode. Available in Zinc. 㖀 ی ZSC - Shaft Collars, designed for installation where only a minimum amount of shaft is visible.