Duckworks - Development of a Table of Offsets

Custom Search

home

indexes

features

Development of a Table of Offsets - Hong Kong

By Ken St.Andre - Auburn, Maine - USA

Hong Kong Style Junk Pelican - Using FreeShip Ship Design Software

Previously I posted a document that demonstrated the offsets for the 18' Super Pelican. Since the Yangtze Pelican is based on the 18' Pelican, I thought I would make a stab at using the same software to develop a concept for a junk rigged Pelican.

I am sure there will be all sorts of thoughts and/or comments about "Why would anybody want to do that?" That is not the point of this paper. This paper is an attempt to show "What if...?" to anybody who does have an interest in the Chinese junk. If you don't have an interest in the Chinese junk... just quit reading.

Design Approach

To begin with, I started with my previous development of the 18' Pelican. I then searched the internet for pictures of Chinese junks since I wanted something that would very closely resemble the actual junk design. Using these photos, I used CAD software to make measurements of the masts and spars as well as the battens and their angles. There are many patterns for the junk rig out on the internet and everybody is free to choose their own preference. I wanted to replicate the real deal.

After looking at many pictures of the junks in Hong Kong harbor, I decided that one of the hull characteristics was the sweeping shear line and the high bow and stern. I decided to build that shape into my "Hong Kong style" Pelican. Drawing on the design concept of the Yangtze Pelican, I have used a raised deck fore and aft with a center cockpit.

I wanted to preserve the "in water" characteristics of the 18' Pelican, so I left the Hull shape below the waterline without any changes. The raised decks at first appeared "boxy" so using the fairing software I pulled the shear line into a fair curve that resembled the Hong Kong junks. The software allowed me to pull the whole thing together using the natural expansion curves of the sides and bottom. This raised and extended the bow transom (all of which is above the 18' Pelican design water line) and increased the rake of the stern transom. The overall length came out to be right at 20'.

The sails in the drawings are patterned after the Hong Kong junk. Actually they are more of a concept drawing at this stage than a technical drawing of the sails. I did not compute exact locations for the centers, sail area, etc. for example. Based on the Hong Kong junk photos, a main sail with 12' boom length would have about 125 sq. ft. of area and the fore sail would have an area of about 37 sq. ft. The mizzen would be a tiny 16 sq ft if you wanted one for looks.

So, here is another concept drawing of an adaptation of the 18' Pelican into a junk rigged boat. If nothing else perhaps it will increase interest in the plans available from Muriel Short. If you have any questions please feel free to contact me at saintk@roadrunner.com.