Great sruff. Thanks Kevin,

I will be interested to know how you mount the rudder, and to follow any research you might have done on this subject. I have read the occasional remark about lines leading from the bottom of the rudder to the bow, to hold the rudder in place – and I must say at first glance it does seem that this would be necessary. The only drawing I have seen which actually pictures it is this one – but it doesn’t show much detail. 

This is a drawing of Free China which was done some time after she reached the USA. The "rudder bowsing line" is clearly shown here (that's not the keel profile, it's an external rope) - but no other detail is given.

I presume that rope is led back to a windlass.

As for hoisting, that's part of the purpose of the high poop I suppose - an attachment point for a conventional tackle, or possibly a windlass.

As far as I know gudgeon and pintles were not used on the ancient junks, and the the stern of the hull proper is occasionally shown as an internal vee which presumably constrains the rudder stock. 

I've always wondered how these gigantic lifting rudders were actually mounted.  

Here is an extract from the Keying "Guide" which gives some idea:

"...  the enormous RUDDER, not hung with pintles and gudgeons, the vessel having no stern post, but suspended to two windlasses by three large ropes made of cane and hemp: one round a windlass on the next deck, and two round a windlass on the upper deck of all, so that it can be raised or lowered according to the depth of the water in which the vessel sails. When the rudder is lowered to its full extent for going to sea, it draws about twenty-four feet, being twelve feet more than the draught of the vessel, and it is steered on this deck. It is also drawn close into the stern, into a kind of socket, by means of two immense bamboo ropes attached to the bottom of the rudder, going underneath the bottom of the vessel, and coming over the bow on the upper deck, where they are hove in taut and fastened. When let down to its greatest depth, it requires, occasionally, the strength of fifteen men to move the large tiller, and even then with the aid of a luff tackle purchase and the best patent blocks. Without this aid it would require thirty men. On one occasion, when the junk was running before a fresh gale, attended with hail squalls, a tiller rope of nine inches was snapped in two like a piece of thread. The rudder is now hoisted up and a small tiller shipped in it on the upper deck. It is made of iron-wood and teak, bound with iron, its weight is from seven and a half to eight tons, and it is perforated with rhomboidal holes. ..."

The scores of lines drawings and sail plans in China Offshore Fishing Atlas shows a huge variety of these large rudders, many of them with stocks, and some clearly with pintles - but these were all records of vessels still in existence in the 1950s, by which time Chinese naval architecture was becoming hybridised with that of the West.

Does anyone have any further detail on the traditional mounting of a Chinese rudder?

Anonymous wrote:

DVV wrote:

What do you think? Opinions and questions are welcome.

I love the lines. No one seems to make sheer lines like that anymore. I am not sure if that means it is just so much easier (and less expensive) to make straight sheer hulls in a factory, or if straight sheers are easier to sail and more sea kindly. It is obvious to me that a hull made with all uniform width planks will tend toward high ends. I would guess straight decks would be easier to walk on too (though that is of no concern in this case). What is the length? It looks like it should be 4 or 5 meters going by the motor size. 3 would be a bit short for a pointy end I think.

I think the shape of the sheer depends from many thing, and tradition has a large part in this. Chinese vessels have high bow and sterns, this being a traditional style sampan replicates those features.

In theory a blunt shaped bow high would be slightly easier to build, but I dont think the difference would be that much.

This is supposed to be 3mt. It is to be used in restricted areas with and there is a limitation in dimensions. The original one should be around the same size.

Hello.

I'm trying to develop a reproduction of a 3mt Sampan of Hong Kong.

This is a traditional local type. Originally used with sails, now motoring.

I attach some pic of my design and of the original boat.

I kept all the peculiar features of these kind of vessel: large overhangs, sampan bow, max beam quite aft, bow and transom in the water. The large opening in the transom is due to the use of a motor, but I would like to add a deep rudder (hopefully rising) and a junk rig of around 7 square meters (Halibut rig?)

What do you think? Opinions and questions are welcome.

DVV