From Appa1990's (https://www.printables.com/social/278703-appa1990/about) file grab, either here or on Thingiverse.

Should scale up fine, smaller will get trickier. It will need supports. Dot of glue for the rudder.

Printed here in PLA, 0.15mm layers.

The sail is designed to work with 0.2mm first layer, 0.15mm for the rest. Colour change after 0.35mm. Setting infill to 0 degrees instead of 45 seemed to work. Form the sail with just not-boilng water with a wine bottle and a chopstic or simmilar.