Mk I chainplates

The Mk I relied on one upper and one lower anchored to a single chainplate. The Mk II (which closely resembles the Mk I, but has a taller mast) gained an extra set of lowers secured on chainplates forward and aft of the main set.

Note the inboard cast bronze stanchion base. These take considerable deck space and, being inboard, are mounted through the deck's balsa core. Because they are so frequently stressed, they can be a point of entry for water that will delaminate the deck, leading to a deck repair like that detailed in Black Arts. If a surveyor finds moisture in the core or you suspect a leak, the bases should be carefully rebedded, or better, the mounting holes should be sealed with epoxy, a process also described in Black Arts in the section on deck tracks.