It's a requirement for all Keelboat owners and any other sailing members participating in racing to be members of SA Sailing.
MYC collects associated fees from the members and pays over to SA Sailing.

We do not insist on this for social members who might occasionally splash about on a sail boat.

Members who join for Canoeing, Rowing or Swimming would benefit from membership with the respective National associations for their sport.  However this is up to the member to arrange - MYC does not do any admin in that regard.