If you are building a semi scale and not too serious craft why don’t you simply make it for yourself it doesn’t have to be that accurate. Like this drawing perhaps?
The pedestal need not be curved but a simple straight sided squaare box if needed or else a bit of dowling and the barrel the tube from a biro pen with balsa blocks and plasticard shield etc etc ? You could get the taper by putting the dowling in a drill and holding a file to it while turning. Assuming you don’t have a lathe

If the scale requires a larger dowel than fits the drill then put a threaded rod [long bolt say 4<6mm] through dowel and chuck that into the drill. You could need that to secure to the boat

Edited By JC Uknz on 15/04/2009 10:56:46
Edited By JC Uknz on 15/04/2009 10:59:57