- Action: To Do List item A0071 – Replace corroded boomkin stay mount brackets.
- Action: To Do List item A0073 - Add ground/bonding path from boomkin stay mount brackets to primary zinc.
- Action: To Do List item A0074 - Determine if external zinc can be mounted on boomkin bracket’s lowest point.
- Action: To Do List item A0106 - Make and install boomkin stay mount bracket stainless steel backing plates with new mount hardware.
- Completed: 11 February 2017
- Cost: $281.13
The first step was to measure and duplicate the existing mount bracket design and new backing plates on paper as shown below. The original mount brackets were suspected to be made of 304-series steel as they were magnetic and the base was 1/8 inch thick. The new material chosen was 316-series stainless steel 0.25 inch thick for the brackets and 0.1875 inch thick for the backing plates.
Based on the design ordered the 316-series stainless steel material precut to 4 and 7 inch long by 2 inch wide pieces from OnlineMetals.com at a total cost with shipping of $141.98. For mount hardware selected 5/16"-18 x 2" Grade 316 stainless steel hex cap screws, nylon insert lock nuts, and flat washers from the Fastenal Company website at a cost of $14.61. Purchased a box of 50 316L welding rods locally for Peso 915 (US $19.06). When the material arrived 2 months later, selected a local Filipino machine shop to fabricate the four sets of mount brackets - two sets are reserved for spares. It took them over 2 weeks to complete at a charge of Peso 4,000 (US $83.33).
Prior to installation of the mount brackets, both the exterior and interior mount surfaces were sanded with 80 grit and cleaned. The brackets and mounting hardware were test installed and had to re-drill a few holes to achieve proper alignment for the backing plates to the mount brackets. Then applied two coats of Interlux InterProtect HS Epoxy Primer YPA420/422 Gray to both exterior and interior mount surfaces. Used a cartridge of 3M Marine Adhesive Sealant Fast Cure 4200FC White ($22.15) to seal the brackets and bolt holes on final installation. After the sealant had cured used a razor blade to trim off the excess sealant on the exterior mount brackets.
In the pictures above, a 10 gauge green wire is attached on the lower mount bolt. This wire is routed aft and attaches to a bolt the secures the installation for the aft primary zinc; the wire run is approximately 4.0 feet long. This wire serves as the ground/bonding path from boomkin stay mount brackets to primary zinc and exterior metal point-to-point continuity check with electrical meter showed a 0.001 level of resistance. This fulfills To Do List item A0073 - Add ground/bonding path from boomkin stay mount brackets to primary zinc, and also To Do List item A0074 - Determine if external zinc can be mounted on boomkin bracket’s lowest point. It was decided not to attach an externally mounted zinc to the mount bracket lowest bolt since the electrical meter continuity check had extremely low resistance and "should" minimize any future corrosive action to the mount brackets.
