No. 237 Maritime Archaeology in the People's Republic of China ...

separated by more than a plank width. The outer layer does
function as a continuous sheathing layer.
Nailing
The planks of the main planking are skew nailed together
through the seams. The skew nails have been driven down
from the upper plank to the lower from the outside of the
hull; during this process the rabbeted seams would help hold
the planks in alignment. There are only three places where
the external face of the inner planking is exposed allowing
measurement of the distance between the skew nails, the
longest of these exposed portions is two metres. It was found
that the skew nails were very regularly spaced at exactly 200
mm! The nail heads are set into small chiselled recesses in the
planking about 90 mm above the plank seam. The nails used
were approximately 200 mm in length (pers. comm. Prof Li
Guo Qing). The garboards were skew nailed to the keel with
nails about 160 mm apart, the strong fastening of the garboards
to the keel seemingly reflects the importance of the garboards
in reinforcing the relatively weak scarfs of the keel structure
in this tradition of construction.
Alignment of butts
All plank butts (see fig) in the main planking are positioned
under bulkheads. This makes it impossible to detect any butts
except by close inspection, and even then the majority remain
hidden. Assuming that the construction was plank-first then
the positions of the bulkheads must have been predetermined.
The butts in the main planking are short half lap joins (fig) or
possibly tongue and groove joins. The lap joins forward of
midships ‘look’ forward, while those aft of midships look aft.
This suggests that the long midships planks were fitted first in
the assembly of each strake, then the strakes were extended
towards the bow and stern. No strake consists of more than three
planks as far as we could tell. The Wen Wu article translated by
Merwin (1977) gives the length of planks as ranging between
a minimum of 9.21 m (presumably the is the minimum length
of planks that remain complete) and maximum 13.5 m which
confirms that all extant strakes are composed of either two
or three planks. The uppermost remaining strake, strake 16
on the starboard side, has only one butt, which is positioned
at bulkhead 6; however, no other butts were identified at the
midships bulkheads 6,7 & 8.
The plank pattern of the main planking is completely
symmetrical port and starboard—if strake seven has a butt at
bulkhead ten on the port side, then there is also one there in
strake seven on the starboard side. The one exception to this is
a long tapered scarf running almost the full distance between
bulkheads ten and eleven in strake nine: on the starboard side
this a genuine scarf between the long midbody plank and a
very broad plank that extends aft from it. But on the port
side, there is a butt under bulkhead ten and aft of it a short
triangular piece extends the midships plank to form the (false)
scarf with the broad after plank—this appears to be a device
to accommodate, or disguise, a mistake made when a butt was
cut at the end of the port side midships plank.
The positions of all the plank butts that could be detected
are shown if figure X. In the five strakes where both ends of
the midbody planks could be seen (strakes 7, 8, 9, 10 & 13) the Figure 91. Plan of planking arrangement showing the butt-joint
arrangement.
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