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Small boats, big oceans and headwinds

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  • 14 Mar 2015 20:59
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    Reply # 3252443 on 3252192
    Deleted user
    Arne Kverneland wrote:

    As these videoclips of "RS14, Stavanger" shows here...

    https://www.youtube.com/watch?v=26lvvcOeml8

    or here...

    https://www.youtube.com/watch?v=vA7zZQVPayY 

    ..the Colin Archers could still perform, when handled by pros.

    Well I used Colin Archer as an example because Marchaj does, but any full keel heavy displacement boat would do as an example, like.. Tahiti ketch, Westsails (Colin Archer copy -  I think), Formosans etc. The point is hulls with a large proportion of their volume below their LWL is less influenced by waves. And "small boats" could be anything below 100' LOD in the world of shipping, which is the context Mr Kwong might be using.


    Last modified: 15 Mar 2015 00:45 | Deleted user
  • 14 Mar 2015 15:50
    Quote
    Reply # 3252192 on 3251843
    Anonymous member (Administrator)
    Gary King wrote:  ..Boats like Colin Archers score well while "modern" light weight fin keeled boats the least. A wooden junk if they are heavy displacement enough are probably somewhere in between a Colin Archer and modern "cruising" yacht. If people can circumnavigate those modern things (they tend to stay in the light weather tropics) then a traditional junk can definitely.


    Remember though that the Colin Archers were not in the small boat category. The engine-less rescue vessels built between 1892 and well after 1910 were about 47' and with 30 tons displacement. Big is beautiful when it comes to capsize screen and sea-kindliness  - until the rig gets too big to operate...

    As these videoclips of "RS14, Stavanger" shows here...

    https://www.youtube.com/watch?v=26lvvcOeml8

    or here...

    https://www.youtube.com/watch?v=vA7zZQVPayY 

    ..the Colin Archers could still perform, when handled by pros.

    Last modified: 14 Mar 2015 16:13 | Anonymous member (Administrator)
  • 14 Mar 2015 00:40
    Quote
    Reply # 3251843 on 3250783
    Deleted user
    John Kwong wrote:Is traditional wooden Chinese hull suitable for big ocean? Lacking a heavy long keel, with a daggerboard near the front, a length to width ratio of 4:1
    Having had a skim of "Seaworthiness The Forgotten Factor" by Marchaj, where seaworthiness means resistance to capsizing when a huge wave hits, displacement is the key, more to the point, the more submersed volume there is the better. And not too much beam either. (Marchaj doesn't like wide hulls.) 4:1 isn't beamy.


    Boats like Colin Archers score well while "modern" light weight fin keeled boats the least. A wooden junk if they are heavy displacement enough are probably somewhere in between a Colin Archer and modern "cruising" yacht. If people can circumnavigate those modern things (they tend to stay in the light weather tropics) then a traditional junk can definitely.
  • 13 Mar 2015 16:16
    Quote
    Reply # 3251413 on 3165641
    Anonymous member (Administrator)

    Forward daggerboard/cb  -  an armchair theory...

    My tongue-in-cheek theory on the forward position of the cb goes about like this:

    Just about all Chinese rigs have been pure fore-and-aft rigs, that is, with no symmetric, downwind-friendly square-sails involved (much unlike the majority of European rigs). Anyone who have sailed fore-and-aft sails, in particular broad versions of them, like gaff sails, knows that beam- and broad-reaching such rigs involves lots of weather helm. The Chinese, instead of adding square-sails, just built bigger rudders. Then, when sailing to windward, to make use of that big rudder, they moved the cb well forward. As a result, the leeway resistance of the junk would be the sum of that of the rudder and the cb. If, on the other hand, the cb had been positioned further aft, to balance out the sail forces, there would have been no load on the rudder when sailing close-hauled, and the cb would need to be twice as big to prevent excessive leeway.

    An additional bonus of the forward cb is that even if one mast breaks or one sail fails, the vessel will still be manoeuvrable with the remaining sail(s).

    Just a thought.

    Cheers,
    Arne

     
  • 13 Mar 2015 14:34
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    Reply # 3251261 on 3165641
    Anonymous

    Interesting question - I don't know the definitive answer, but I have always assumed that it is to better hold the head to the wind It will also balance the very large rudder - to bring the CE forward enough the dagger has to be well forward. These are probably two sides of the same coin.

    Chris

    Last modified: 13 Mar 2015 14:34 | Anonymous
  • 13 Mar 2015 14:15
    Quote
    Reply # 3251234 on 3165641
    Anonymous member
    Thanks Chris and David for the reply. Can anyone tell me the reason why the position of the daggerboard of traditional junk is near the bow and not at the CLR like modern fin keel ?
  • 13 Mar 2015 10:30
    Quote
    Reply # 3251019 on 3250783
    Deleted user
    John Kwong wrote:Is traditional wooden Chinese hull suitable for big ocean?
    John

    The large trading junks which plied their trade up and down the Chinese coast in synchrony with the reversals of the NE and SW monsoons had no need of a particular ability to sail against the prevailing winds, nor to sail far from the coast.  The Fukien trader, of which the Keying was almost certainly an example, was just such a trading junk. The accounts of the voyage of this craft from China to London via New York in 1846-8, in the hands of a mixed Western and Chinese crew demonstrated that while very seaworthy and capable, it was a very poor performer with the wind significantly forward of the beam.

    Unlike their larger trading cousins, the fishing vessels could not afford to ignore windward capability. The fishing junks of the northern and eastern coast of China had to get to their fishing grounds, which were very often 100 miles or more offshore, and to return with their catch still fresh. They had to be, and were seaworthy enough to operate far from the Chinese coast, where weather conditions could often be extreme. Very often, their catch had to be returned to large towns up and down the coast, such as Shanghai, where they would be unloaded for sale. The junk would then return to its home port. This requires a triangular course, necessitating not only making to windward, but making good time if their catch was to be fresh and saleable. Many of the fishing vessels from more southern ports in Guangdong had their fishing grounds around Hainan Island to the southwest. Whatever the monsoon season, either the outward or the return trip must very often have required work upwind.

    Since the voyage of the Keying in 1846-48 a great many traditional wooden junks have proven themselves capable of ocean crossings. I find it significant that many of the most successful were fishing junks. 

    Chris
  • 13 Mar 2015 04:30
    Quote
    Reply # 3250837 on 3250783
    Deleted user
    John Kwong wrote:Is traditional wooden Chinese hull suitable for big ocean? Lacking a heavy long keel, with a daggerboard near the front, a length to width ratio of 4:1


    It seems to me that one can cross oceans in just about any kind of seaworthy boat and expect to make shore on the other side, just look at the crazy variety of boats that make ocean crossings in this modern age of extreme adventure. Back about 50 years ago there was a traditional Chinese hull with traditional junk rig that made a voyage from Hong Kong to New Zealand. The story is recounted in a book named 'The Voyage of the Golden Lotus'. The book is world famous in New Zealand!

    The thing that is more likely to influence at least my choice of hull would be what amount of comfort, windward ability, and speed do I want, weighed up I guess against the available budget.  

    On our return voyage from New Caledonia to New Zealand 18 months ago on 'Footprints' we experienced the type of ocean sailing I have always wanted to avoid. That is 4 days of hard on the wind in 25 to 30 knots wind speed with waves so large that the GPS showed us slowing down as we reached the crest of each wave and speeding up as we went down the back of the wave. We had no choice but to keep going and although 'Footprints' is not the ideal type of boat for this work she kept plodding on making 90 to 100 miles each 24 hours, and we survived the very unpleasant conditions.

     

    Last modified: 13 Mar 2015 04:41 | Deleted user
  • 13 Mar 2015 01:13
    Quote
    Reply # 3250783 on 3165641
    Anonymous member
    Is traditional wooden Chinese hull suitable for big ocean? Lacking a heavy long keel, with a daggerboard near the front, a length to width ratio of 4:1
  • 08 Dec 2014 13:46
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    Reply # 3166048 on 3165641
    Deleted user

    Last modified: 08 Dec 2014 13:47 | Deleted user
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