Borobudur 1 Pm

BOROBUDUR SHIP RECONSTRUCTION: DESIGN OUTLINE The intention is to develop a reconstruction of the type of large outrigger vessels depicted at Borobudur in a form suitable for ocean voyaging and recreating the first millennium Indonesian voyaging to Madagascar and Africa. DISTANCES AND DURATION OF VOYAGES Distances: Sunda Strait to Southern Maldives: Approx. 1600 n.m. Maldives to Northern Madagascar: Approx. 1300 n.m. The vessel should be capable of transporting some 25-30 persons, all necessary provisions, stores and a cargo of a few cubic metres volume. Assuming that the voyaging route to Madagascar was via the Maldives, a reasonably swift vessel could expect to make each leg of the voyage in approximately two weeks in the southern winter months when good southeasterly winds can be expected. However, a period of calm can be experienced at any time of year and provisioning for three-four weeks would be prudent. The Maldives would provide limited opportunity for re-provisioning. It can be assumed that rice sufficient for protracted voyaging would be carried from Java. As far as possible the reconstruction will be built using construction techniques from 1st millennium Southeast Asia: edge-doweled planking, lashings to lugs on the inboard face of planks (tambuku) to secure the frames, and multiple through-beams to strengthen the hull structure. There are five bas-relief depictions of large vessels with outriggers in the galleries of Borobudur. They are not five depictions of the same vessel. While the five vessels are obviously similar and may be seen as illustrating a distinct type of vessel there are differences in the clearly observed details. The depictions are probably not all by the same artist. Following van der Heide (1929), I shall use the plate (Afbeelding) numbers from van Erp’s (1923) paper to identify the Borobudur ships. Volume <ul style="display: flex;"><li style="flex:1">Component </li><li style="flex:1">Calculation basis </li><li style="flex:1">Amount Weight </li></ul><2 tonnes including containers, Water for drinking and cooking approx 33m Thirty persons, twenty-five days, not less than 2 litres per person/day 1500 litres Average 50kg per person Sleeping space 1.6m x 0.45m for 25 persons Ships' compliment 1.5 tonnes 182m Thirty persons, sixty days, 0.5kg per day approx 1.53m Rice 900kg A fire would be kept smoldering at all times when a stronger fire was not required Firewood for cooking 3<ul style="display: flex;"><li style="flex:1">~1 tonne </li><li style="flex:1">2 m </li></ul>Salt fish, plantains, tubers, tamarind, Other foodstuffs etc. 3~0,5 tonne 0.5 m Approx 2 tonnes of spices and other high-value commodities 3m Cargo Other <ul style="display: flex;"><li style="flex:1">~2 tonnes </li><li style="flex:1">4</li></ul>3Personal belongings, e.g. sleeping mats, tools; spare ship's gear; ~0.5 tonnes 2 m However, these are not sailing vessels — they are motorised and use multiple stays to hold up the outriggers. Sailing vessels impose much more load on their outriggers and outrigger booms. The largest sailing outriggers of recent decades have been the perahu sande and perahu pangkur of the Mandar people from the west coast of Sulawesi, and some very large jerangkat built on the western coast of the Gulf of Bone and used as FADs (Fish Aggregating Devices) anchored in very deep water to the south of the Gulf. These vessels have been up to about 10-11m length and the largest pangkur have been able to load more than 5 tonnes. In the first half of the 20th century, outrigger perahu paduwang from Madura were probably slightly larger than the vessels mentioned above. However they seem to have regularly employed human ballast on the weather outrigger to enhance stability. The total stowage space indicated by these approximations is 133m. The weight calculated is approx 8.5 tonnes. Depending on design, the vessel might also need to carry a tonne or two of ballast. Approximately 182m of sheltered space would be required for most of the ship’s company to sleep. It is assumed that some persons would be on watch at all times. MAXIMUM SIZE OF OUTRIGGER SAILING VESSELS There are vessels without outriggers depicted at Borobudur but the five large vessels depicted in detail all have outriggers. The Borobudur ships appear to be fairly large. Sizes up to 25m have been posited for the largest example: Erp 6. Heide (1929) offers a more sober estimate of 12-15m based on the number of oar ports. This allows about 1m for each oarsman. In recent decades some very large outrigger vessels have been built in Indonesia and the Philippines. The largest pangku r , s ande and jerangkat had very large and long bamboo outriggers. Pangkur and boom is increasingly susceptible to breaking off when pitching into a headsea. A Selat Badung jukung with a 6m long hull has outriggers 9m long, mean diameter at least 125mm and buoyancy of about 100kg. (0.0625 x 0.0625 x π x 9m = 0.1103m) Using these proportions and assuming that the largest bamboos would have diameter about 200mm, the largest possible outrigger canoe is about 10m long. perahu pangkur Extrapolating from that calculation, outriggers of sande usually have outriggers more than 150% the about 300mm diameter with buoyancy of about length of the hull. They normally depended entirely 1.3 tonnes would be required by an outrigger vessel on outriggers for stability and sometimes made a little more than14m long. Such a vessel, designed <ul style="display: flex;"><li style="flex:1">fairly long, open-sea voyages. </li><li style="flex:1">with a long narrow hull would scarcely have the </li></ul>The maximum size of pangku r , s ande and jerankat capacity to carry the proposed passengers, is probably determined by the maximum size of provisions and cargo. Therefore it can be bamboos available. Since the sail area that imposes concluded that it is not possible that an outrigger heeling loads increases as the second power of the vessel, designed to derive all its stability from length of the vessel, the volume (buoyancy) of the outriggers, could be built of a size large enough to outriggers needs to increase at the same rate. In carry the proposed passengers, provisions and other words the diameter of the outriggers must cargo. increase in proportion to an increase in hull length. This leads to engineering problems as size The outriggers shown on the Borobudur ships are increases: if the length of the outriggers increases not like the long outriggers of the large outrigger in proportion to the hull length, the long projection vessels of the 20th century. They appear short and of the outriggers forward of the forward outrigger small relative to the size of the ships. THE DESIGN AND PURPOSE OF THE BOROBUDUR OUTRIGGERS The relatively small outriggers of the Borobudur ships, with their short projections forward and aft of the booms would be relatively robust but they would provide little buoyancy and stability relative to the size of the ships and their sail area. Single or double outriggers? In four of the five Borobudur ship depictions only the windward side of the vessel is shown. Whether the vessels are double outriggers with another 19th century perahu paduwang dhoni means “pilgrimage boat”. Single outrigger canoes are used on some parts of the north coast of Central and West Java. They have a single outrigger boom and they shift the outrigger from one side to the other when changing tack. The arrangement is simple, loose, and temporary in appearance. It is not suitable for larger sea-going vessels. The Borobudur ships have three or four outrigger booms of complicated construction: it does not look like an arrangement that could be shifted when changing tack. Large single outrigger, non-shunting, canoes were outrigger on the leeward side or single outriggers built at Macassar, South Sulawesi. These vessels carrying a flying outrigger on the windward side were built exclusively for racing and were a single only cannot be determined with certainty. outrigger version of the double outrigger However, Erp 10, which has its sail partly furled, jerangkat. They had one very large outrigger and has that sail on the side of the mast towards the employed a lot of movable human ballast when viewer which suggests that we are looking at the racing (Collins 1936). leeward side. Four of the five depictions show the It seems unlikely that the Borobudur ships were port side of the vessel but Erp 9 shows the single-outrigger craft. starboard side so outriggers are seen on both sides Double outrigger canoes are not widely used on <ul style="display: flex;"><li style="flex:1">of the hull though not simultaneously. </li><li style="flex:1">the coasts of Java but they are more common on </li></ul>Most single outrigger vessels are designed to tack neighbouring islands including Madura and Bali by “shunting” in order that the outrigger remains where sophisticated designs exist. on the windward side when they change tack. When a vessels tacks by shunting it reverses The Borobudur outriggers have a number of direction and reverses ends — the bow becomes characteristics that make them significantly the stern and vice versa — the steering gear must different from the outriggers of sailing canoes of be shifted from one end to the other and the rig more recent times. reconfigured to drive in the opposite end. Such vessels are necessarily longitudinally symmetrical Length of the outriggers — the ends are very similar — and they have a The outriggers of Indonesian vessels, including simple rig usually with the mast positioned those first depicted by Europeans in the late 16th <ul style="display: flex;"><li style="flex:1">midships. </li><li style="flex:1">century, have generally been similar in length to </li></ul>The Borobudur ships do not exhibit longitudinal the hulls of the canoes they were fitted to. In many symmetry and do not have rigs that could be easily cases they are longer than the hulls. The Borobudur <ul style="display: flex;"><li style="flex:1">reversed. </li><li style="flex:1">ships all have outriggers shorter than the waterline </li></ul>There was a type of a large single outrigger vessel length of their hulls. Erp 6 (which appears to be from Sri Lanka, the yatra dhoni, which did not the largest vessel) has an outrigger only 0.54 the shunt. Unfortunately the last of these fell into length of the hull. Erp 8 has the longest outrigger disuse early in the 20th century and it is not known at 0.79 the hull length, it has four outrigger booms how the yatra dhoni was operated. The hull form while the other vessels have three outrigger booms. of the yatra dhoni had enough beam and stability <ul style="display: flex;"><li style="flex:1">Erp No. </li><li style="flex:1">Outrigger length as decimal </li></ul>if ballasted to sail without an outrigger (Vosmer 1993). It seems possible that the outrigger could be shifted from one side to the other (with some difficulty) and that the yatra dhoni was used mainly for long monsoonal voyages to and from India when wind direction might be consistent for the entire duration of the voyage. The name yatra fraction of hull waterline length Erp 6 Erp 7 Erp 8 Erp 9 Erp 10 0.545 0.585 0.79 0.64 0.750 On all but one of the Borobudur ships the there is another outrigger on the inboard-underside outriggers are doubled — there are two outrigger of the boom. components which I presume are bamboos, one The booms or connectives (it is not clear which on the inboard side of the outrigger boom/ they are) project below the outriggers. connective, one on the outboard side. Some of the Indonesian vessels recorded by Captain Paris in the 19th century (Paris 1841, Reith 1992) had outriggers of relative lengths that fell within the range illustrated in the Borobudur ships. They were mostly from the Moluccas and neighbouring regions of Eastern Indonesia where Detail from Erp 6 shows outrigger connectives that project well below the outrigger outriggers have remained relatively short in more Volume of the Outriggers recent times. Light weight timber rather than bamboo is often used for outriggers in Eastern Indonesia (in some areas suitable bamboo is unavailable) and outrigger craft depend on movable human ballast for stability. By contrast, in areas closer to Java (e.g. Bali, Madura) outriggers are usually significantly longer than the canoe they are fixed to. Typically relatively large and fast sailing canoes have a crew of only one or two persons and depend on the buoyancy and hydrodynamic lift of the lee outrigger for stability. The shortest outriggers (0.525 relative to hull length) in a survey of sailing vessels illustrated in the literature were on a large kora kora from Dorey off the western end of New Guinea (Paris 1841). The kora kora had a fairly capacious planked hull and a length beam ratio of less than 4:1 which could sail without outriggers if properly ballasted. Most outrigger craft have a quite different type of hull, built up from an unexpanded dugout canoe and therefore of very narrow beam and not suitable for sailing without outriggers. The Borobudur outriggers do not appear large in diameter. They are shown with diameter about the same as that of the outrigger booms or less than that of the booms. This relative proportion probably reflects the large size of the ships and the upper limit to the size of bamboo available. A Borobudur vessel of about 14m length would have outriggers about 8m in length: if the outriggers were about 200mm diameter, and the outriggers were doubled (inner and outer outrigger) the buoyancy of the outrigger would be about 0.5 tonne which is significant but not in proportion to the size and sail area of the ship. Fairings Erp 6 shows a fairing on the forward end of the outrigger. The other four Borobudur ships have no outrigger fairings. Fairings similar to those on Erp 6 have been used in recent times so that the bamboo outriggers can cut smoothly through the water. They are a standard feature of most sailing outrigger canoes. All the features discussed above suggest that the outriggers of the Borobudur ships were not intended to provide stability to the extent that the leeward outrigger of double outrigger canoe normally does: they lack volume and therefore the buoyancy to resist heeling. They are not faired to cut through the water. The outrigger booms or connectives project below the outriggers and would cause significant drag to the detriment of speed and steering if depressed into the water. Erp 9 shows its lee outrigger apparently flying clear of the water since the outrigger boom (connective) ends can be seen projecting below the outrigger. Attachment of Outriggers to Outrigger Booms There are several different ways of attaching outriggers to the outrigger booms used in Indonesia. In some cases there are curved timbers connecting the outriggers to the booms (these are termed “outrigger connectives” by Haddon and Hornell). Whether there are connectives or the outriggers are secured directly to the booms, the outrigger usually lies under the boom or connective. Alternatively the boom or connective penetrates the outrigger. On all the Borobudur ships there is an outrigger attached on the outboard side of the boom/connective. On all except Erp 8 If it is concluded that the outriggers are not Larger and wider galleries, running the full length primarily intended to provide stability another of the hull, were a feature of 18-19th century perahu explanation of their use is required. Like the lancang. outriggers of the 19th century bouanga from New Guinea, drawn by Capt M. Paris, the outriggers The galleries seen on the Borobudur ships are might be seats for paddlers to propel the vessel in large, enclosed, and exhibit complex structure. <ul style="display: flex;"><li style="flex:1">calms and in martial use. </li><li style="flex:1">Again martial use is suggested with a need to </li></ul>If the outriggers are not designed to be the vessel’s protect the oarsmen from spears and arrows. primary source of stability then the hull form will not be a typical outrigger canoe hull form. Instead All the Borobudur ships except Erp 9 have a deck it will have a broader, more stable and more house with a pitched roof positioned aft of the main <ul style="display: flex;"><li style="flex:1">capacious hull form. </li><li style="flex:1">mast. The deck houses appear to be small and are </li></ul>unlikely to represent all the accomodation space in the ship. <ul style="display: flex;"><li style="flex:1">THE SUPERSTRUCTURES </li><li style="flex:1">HULL PROFILES </li></ul>The Borobudur ships all have considerable The upper parts of the hulls of the Borobudur ships superstructures obscuring their hulls. There are are hidden by the galleries and the bow and stern outboard galleries for rowers along the full length screens. of the hull. In the bow and stern tall screens Four of the five Borobudur ships have a straight, surround the stem and sternpost. Heide has forward raked profile to the bow. Erp 9 has a proposed that the bow and stern screens are curved, forward raked bow profile. In Heide’s protective structures for use in warfare. This seems interpretation, Erp 7 and 8 both have an external very likely. Later warships used by Sulu sea pirates stem. Erp 6 does not obviously have a stem in the had a heavier timber screen in the bow to offer lower part of the bow, but there is a high prow <ul style="display: flex;"><li style="flex:1">some protection from cannon shot. </li><li style="flex:1">timber projecting above the bow screen. Some </li></ul>types of Indonesian perahu are built without a stem (and also without sternpost). These include the Javanese perahu jegongan. None of the Borobudur ships show a sternpost. However, very little detail of hull structure is 19th C Sulu Sea vessel with bow screen The tall screens seen on the Borobudur ships would create much windage which would be detrimental to sailing performance and might not be fitted to ships engaged on long voyages. The tall screens are fitted on top of large through beams and wing-like projections in the bow and stern. Both the heavy through beams (polangan) and the wing-like transoms (kopengan) have been features of some Javanese and Madurese vessels until the late 20th century. In some examples those wings support the ends of small galleries (ambeng) built out from the hull. Stern of perahu kacik showing kopengan supporting an aft gallery shown in any of the depictions.All show an inward HULL FORM raking, recurved profile to the stern. This kind of Little information about hull form can be derived profile has remained a stylistic feature of a number from the Borobudur iconography. The bows and <ul style="display: flex;"><li style="flex:1">of Javanese perahu types. </li><li style="flex:1">sterns appear to be sharp rather than bluff. The </li></ul>Heide traces some evidence of hull shape below underwater body of the hull is not shown and the the waterline in Erp 6 and 7. The bows do not show bas-relief does not provide a fully threea cutaway forefoot but in the stern there is a curved, dimensional representation that would allow cutaway heel profile. Again, this is typical of assessment of beam. Javanese perahu design. Indeed the perahu Hull form must be inferred from archaeological konteng of East Java when planked up to increase data and from critical use of more recent freeboard and cargo capacity has a profile much ethnographic data. like a Borobudur ship. Midships cross-sectional shape Afairly large number of Medieval shipwrecks have been discovered and investigated in Southeast Asia. The vessels discovered at Butuan in the Philippines illustrate a relatively small and sharp type. A larger and more capacious type has been identified as a South China Sea hybrid type combining some Chinese construction techniques with SoutheastAsian hull form and edge-doweling of planks. A large wreck discovered near Palembang, Sumatera probably represents a version of the type with entirely indigenous Profile of a planked up perahu konteng structure. All these wrecks exhibit similar crosssectional shape. They all show hollow deadrise and fairly slack turn to the bilge. None of the Because of the full-length galleries it is not wrecks include the remains of the topsides (with possible to see the rail of the hull and therefore the possible exception of Butuan 5). Ethnographic the freeboard cannot be judged. However, it is data suggests that the topsides were flared rather unlikely that outrigger booms would cross the hull than vertical since vertical topsides are virtually above the height of the rail. Clearly the lower unknown in the region. However, if the rowing outrigger booms pass through the hull; possibly galleries are fitted outboard of the topsides, the the upper outrigger booms rest on the rail. The flared topsides would seem to interfere with the hulls do appear to have considerable freeboard and use of the galleries. the lower outrigger booms appear to be well above the waterline. It is not proposed that the freeboard/ Length-beam ratio, beam-depth ratio length ratio measured from the depictions could The iconography gives no clear indication of the be taken as representing the actual ratio. Distortion, ratio of proportions of the hull. As noted above, exaggerating freeboard, is more or less a standard outrigger vessels usually have very little beam <ul style="display: flex;"><li style="flex:1">feature of ship iconography. </li><li style="flex:1">relative to their length and depth. Non-outrigger </li></ul>If the hulls do have considerable freeboard, then Indonesia vessels very often have length-beam they will either have fairly considerable beam to ratio of about 3:1 and beam-depth ratio of not less provide stability or they are narrow canoe like hulls than 2:1. (“Depth” here means moulded depth of deriving all their stability from outriggers. But for the midsection and has no connection to draft.) <ul style="display: flex;"><li style="flex:1">reasons given above that seems unlikely. </li><li style="flex:1">These ratios produce a hull with very large righting </li></ul>moment (stability) at low and moderate angles of heel making outriggers totally unnecessary. Indeed, such a hull form, when rolling in a beam sea would tend to immerse and damage outriggers References if they were fitted. The 19th century kora kora Burningham, N. 1989. The Structure of Javanese illustrated by Paris has a length-beam ratio of 4:1

Borobudur 1 Pm

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