Varifold VF2SDA Zinc Anode
The Varifold saildrive zinc anode is one of three Varifold folding sailboat zinc anodes stocked by King Propulsion, the USA dealer for Bruntons Propellers.
Varifold Saildrive Zinc Specifications
The Zinc is designed for the VF70 race style Varifold folding propeller. It was designed to be surface mounted flush within the hub of the propeller and therefore has very low parasitic drag when properly maintained.
The anode is different to the other two standard zincs offered by Bruntons Propellers in that it consists of two horse shoe shaped anodes that fit into a machined groove on the side of the propeller hub. Each piece of the anode is held in place by a 316L Stainless Steel countersunk bold on either side of the hub to keep it flush and in place.
Installation of the Varifold Zinc VF2SDA
The installation of the saildrive zinc VF2SDA is very straight forward and can easily be achieved underwater should it be needed. Unlike the other zincs in the range it is not mounted atop of the gearing system but on the side of the hub. By far the hardest aspect will be removing the outgoing zinc. This should be regularly monitored and wear rates can vary depending on many factors including where you berth (steel piers etc.). We recommend not letting the zinc anodes wear below 50% of their volume and for most applications this is typically a season or two, again depending where and how you sail.
Removal of the Stainless steel bolt needs an M4 metric Allen wrench, all of the Varifold range is specified with metric fasteners so it would be a good idea to keep a set of wrenches covering your propeller onboard. Once both fasteners are out the two shells should either drop away or require some gentle persuasion. A large diameter pipe wrench can be used around the entire sail drive zinc to break it free. If the gaps between the saildrive zinc pieces are visible then a flat blade screwdriver to start the removal may also work. It is important not to be too aggressive and damage the hub during this point!
Once the old zincs are removed, the hub should be inspected for damage and the channel that the zinc sits in cleaned to remove any residual zinc, marine growth or hard shell fouling. This is important as the efficiency of your new zinc relies in it being in contact with as much of the parent metal of the hub as possible. This may require a wire brush or emory paper to clean it but again try not to remove parent metal as much as possible.
Once everything is clean, the zinc can be installed. Both halves should sit into the channel without any issues. The bolts should again locate and once tightened look like the photo shown above. The zinc should be flush with the hub again as shown above and ready to be returned to the water for service.
Final thoughts on the Zinc Anode
Incidentally, the other part that needs to be services on a regular basis is the buffer pads (seen black on the photo). These are the cheapest part we sell but are responsible for so much. The buffer pads cushion the blades as they open and without them the blade can develop structural issues from the loading – be sure to check them!!
Lastly, keep an eye on the zinc during the year, steel piers, electrical connections or heavy onboard power use can all cause the zincs to wear faster. Loss of the zinc will make the cathodic process inherent in the boat pull the zinc from the propeller instead giving you a pink propeller. This means it is rich in copper and hence softer. This is one of the main causes of early propeller replacement so be sure to keep an eye on things
For any additional information call the office on (757) 739-2050 or get in touch using Email King Propulsion