Stage 15
Fit masts to ships.
Stage 16
Base models, if doing so.
Stage 17
Spray varnish the ships.
Stage 18
Apply rigging. (Sorry, no detailed description - buy the Langton book, it is much easier!)
Stage 19
Apply ratlines - I used the old rigging material that Langton used to sell. Langton now produce the ratlines in brass, though I have not purchased any of these and cannot comment on how they compare with the mesh.
Stage 20
Apply flags to the models.
Note: I misplaced the ships boats and completed the models without and sent the ships to 
Editor in Chief Bill 
. A day later, the ships boats appeared!!!!!