I am installing a tabernacle on a DS-II and need to decide what fasteners to use to connect the mast to the aluminum casting seats. Galvanic corrosion is not an issue because of a freshwater environment. The options seem to be 1) to drill and tap for SS machine screws, 2) use aluminum rivets or 3) use SS rivets.
For machine screws I was thinking 3 or 4 screws, for each seat, either 8/32 or 12/24. This would make it easy to remove the tabernacle if needed and be very strong. At the same time, the screw heads may require a little bit of filing on the edge of the mast partner to create enough space. Furthermore, the strength of the screws could cause expensive mast damage in case of a shroud failure if the edge of the tabernacle seat did not break off.
For rivets I was considering four 3/16" rivets on each mast seat with a grip of 1/4". This would eliminate the space issue in the mast partner but raises the question of aluminum vs SS from a strength perspective, especially when lowering and raising the mast and encountering some sideways motion.
Any thoughts will be appreciated. Maybe there is a standard way of accomplishing this that has worked and I am making it too difficult.
Thanks.