Page 41 - Loss of the VOC Retourschip Batavia, Western Australia, 1629

The chaplets
All three types of bronze guns have different methods
ofconstructionofthechapletorcrownpiece.Thefunction of the chaplet is to support the bore plug or kernel in the mould before and during the casting of the gun. The complex process of making a mould for a gun required, fIrst, thatamodelofthegunbemade.Aroundthiswascast a mould and the original model was then destroyed and removed, leaving the mould into which was poured the molten bronze. In the 17th century, guns were cast with a plugrunningdownthecentreofthemouldtoform thebore of the gun. Later, in the 18th century, for various reasons, it was found easier to cast guns solid, and then drill out the bore. To support the bore plug, a chaplet was used at the bouom (vent) end of the bore. This usually consisted of a round iron ring which held the cylindrical bore plug. Projecting from the ring were three or more pins which wereauachedtothewallofthemould.Thus,whenthegun was cast, the bronze fIlled up the cavity and surrounded the chaplet; the plug would then be broken-up and removed leaving the cylindrical bore with the iron chaplet cast into the bronze. There is an excellent series of engravings in Diderot (1763): Fig. 79 of Plate 14 shows the completed mould (see also GiIlispie, 1959); Fig. 80 shows the bore plug with the caption:
Lenoyoudel'0J7U!.despieces.ains;quel'onlesfondoittoules percles cl l'ancie11JU! maniere, abrogle. par /'ordo11NUJC1! rapporlee ci-dessus. Le noyau Itoit compose d' UM barre. de fer cylindrique. en/ourle defil defer. & revelu de lerre. &. potee'; Fig. 82 shows the chaplet with caption: 'Chape~tqui servoit a soute.nir le noyau lorsque /' on fondoil les pieces cre.uses.
Norton (1628) also describes the chaplet, although he does not mention it by name: 'There must also bee a smooth and equall CiIlinder, whose Dyarnetremust be just theheightoftheBore,andmadeofthesameearthmoulded upon a strong Iron square Barre, and upon a cord woulded about the same, therewith to make the soule or concave hollow CiIIinder of the Peece, by placing it (by helpe of the Base and Muzzle-ring) exactly in the midstofthe vacuity of the outermost Colume, which when the Patterne or ModeII shall bee taken out, will remaine hollow to receive the metall that must make the body of the Peece.' Wignall (1973) discusses chaplets and suggests that English gun- founders did not use chaplets.
Each type of bronze gun found on the Balavia shows minor differences in the mounting of the chaplets. Evi- dence from the van der Put guns (BAT 3627 & 3640) suggests that the chaplets of these guns did not pierce the wall of the mould, because two of the four arms of the chaplet do not penetrate the outer bronze surface of the gun. At thesepoints, there is a thin layerofbronze(1-3 mm) between the ouler surface of the gun and the hollow end of whal was once the end of the iron chaplet arm. This suggests that the arms of the chaplet rested loosely in the mould, inevitably toUChing the walls o f the mould in only two places (the points at which the chaplet appears to pierce the mould). It is, thus, possible to deduce how the
mould was arranged. Firstly, if the chaplet was mounted loosely in the mould, it could only be sel in place if the caseabel end of the mould was open. It would be impos- sible to insert the chaplet through the muzzle end of the mould, as the diameter of the muzzle at that point would be too small to allow the entry of the chaplet which would have a diameter equal to the breech. Thus, the bore plug or kernel bar was put in place and the chaplet slipped over the end to locate the plug in place. The caseabel of the mould was then sel in place on the mould and the muzzle end of the bore plug fIxed in some way. Presumably, the upper auachments for the plug would have been sel in the head of the mould (the part to be removed after casting) which would explain why they do nol survive.
The pair ofguns made by Mews (BA T 3638 and 3639) were made using a different construction. The chaplet appears to penetrate the mould; there is a clear indication of four holes, and the edges of these holes are sharp and pronounced. In this case, itis not clear how the chaplet was set in place, although this may have been done al the time of making the original positive and, subsequently, incor- porated in the mould.
The purpose of the unusual square holejust forward of the dolphins on the Henricus Mews guns is not clear. It is unlikely that it is a chaplet or has any function relaled to the support of the kernel. It is possible that it is a fitting for a sighting or leveling instrument. Norton (1628):94 illus- trates a gunner's level which could sit on top of the gun. It is feasible that such an instrument could be located using an iron attachmenl lug, cast into the body of the gun. Other known Meurs guns also have this feature.
Chemical analysis
Chemical analysis was carried oul on the fIve bronze
guns to detennine the composition of the trace elements. The analysis was carried oul by Dr Ian McLeod, of the Laboratory for Materials Conservation and Restoration, at the Western Australian Maritime Musewn. The results (Table 1) show that the material is a bronze with little obvious variation in the trace elements. BAT 3637 has a much lower tin content than the other four guns, and while there may be good correlation between the three different types of guns in the tin contenl, there is no obvious correlation with the other elemenlS. Some work has been carried out in Europe on the analysis of trace elements in bronze ordnance, in particular Riederer (1977) has exam- ined the composition of 254 guns in various museums, mainly in Austria, Gennany, Italy and France. Riederer groups the various guns in Fig. 8 by plotting the percentage lead against percentage silver, the only two examples of guns from the Netherlands in this analysis are both from the Hague, made by J. Maritz in 1773 and 1785 respec- tively. Their composition is unlike the Balavia guns, particularly in the leacVsiIverratios (MaritzO.30%,u.11 %). Obviously, the tiny sample analysed by Riederer is hardly representative of all Netherlands guns, and more analyses are required.
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