by Peter Kortens
The project was to put a lead “jelly tip” on the end of our Navigator Kotuku’s centre board and had nothing to do with an “anchor”. We used the existing centre board to make a concrete mould, mounted the SS rods in this mould, poured the lead, chopped off the appropriate length from the centreboard, drilled the holes and then bolted them together. The “U” shaped trident was set 150mm into the lead leaving three 150mm long threaded rods exposed (see the photos below and sketch above).
The design included three 300mm long SS threaded rods buried 150mm into the
centre board. I purchased a one metre long length of 12mm threaded 316 SS
rod and formed a U shape from 700mm of it. The remaining 300mm was then
welded to the inside of the U giving me a three pronged trident. This was
then held in place in the mould whilst the lead was poured. Apart from the
slight movement during pouring, it all worked out well.
Kotuku on Launch Day