The original Toshers had a stern profile that allowed for a prop to be forward of the rudder. The keel had a curve or rocker as shown in the picture below.
The green is the original profile and the area with blue bits is an extension to the heel and the brownish area is the prop area filled in with foam core between epoxy resin and glass matting. The blue heel is polyester resin with glass matting.
The original timber heel extension that allowed for a deeper rudder, while reasonably intact had plenty of timber worn away form regular grounding in its mud berth over the years. I therefore decided to replace with Iroko.
The picture above shows the Iroko shaped to the keep profile. Also shown is a hole that was previously filled in that was weeping slightly in my leak test as described earlier. I cleaned out the previous repair and filled wit polyester and chopped strand. A 100 mm square mat was bonded toe inside with polyester to reinforce the repair.
A suitable piece of Iroko was shaped to the keel profile and bonded with West Epoxy. The original blue heel and prop area was faired with West Epoxy and Colloidal Silica thickened to a mayonnaise consistency. To achieve a fair surface Peelply was laid over the thickened resin and with a flexible filling knife the area was faired to a good first pass prior to fairing with sandpaper.
Having faired the area to a smooth transition the area including the Iroko was sealed with a number of coats of epoxy. Each coat was applied during the gel transition phase of the cure to allow for a chemical bond between the coats.