The owner of Jade (#187) also owns Hornpipe (#38) and has refined the process of that used in #212 to reduce labor time and costs with little or no loss of functionality. Fiberglass floors are fabricated off the boat. The floors are an inverted L-shape (with flange at the top as in the J/35) eliminating the stainless steel angle brackets used in #212. The fiberglass mast step plate bolts directly to the flange. The floors are tabbed into the bilge with biaxial tape and biax/mat in the same manner as in #212.
For installation the old steel step is unbolted from the keel bolts and discarded. The keel bolt nuts and washers are re-fastened. The cabin sole is leveled in both fore/aft and port/starboard directions by adjusting jack stands. A simple jig holds the two new floors properly positioned by a stop that contacts the front end of cutout in the cabin sole to set the fore/aft position. The new floors will need some trimming to fit the bilge profile, while still mounted to the jig plate. The jig plate must also end up level in both directions while fitting closely in bilge. The floors are fastened into the bilge with thickened epoxy. Once the epoxy has cured the jig plate is removed and the floors are tabbed in place with biaxial fiberglass tape and epoxy resin. The step plate with mast plug or socket is mounted to the floors and the step is ready for the mast. Before re-stepping a section of the mast corresponding to the change in height of the new step (over the old one) may be cut off or, rig could be raised 4-5 inches using toggles etc.
This method uses two additional floors and thus improves keel to hull rigidity over the factory design (see note) almost as much as the floors in #212 but has the advantage of not having to remove a portion of the cabin sole to install. The mast plate attachment is simpler, and eliminates the two angle brackets used in #212. Graham will be able to supply a complete kit for this much improved mast step. Kit contains four main fiberglass components: Two solid fiberglass floors, a fiberglass step plate, and a plug that fits snugly inside the mast, which is bolted to the step plate.
Note: There is nothing inherently wrong with the keel to hull rigidity in the 10M as it came from the factory. Adding new floors to support the mast has the added effect of increasing keel to hull rigidity but that is not the purpose of the design nor is it a necessary modification.
New floor trimmed to fit and ready to tab in place.