“Popo” Outrigger Canoes of the Central Caroline Islands

Flying proas of the Caroline Islands, from Adm. Paris. (click any image to enlarge)

In 1983 and 1984, Steve Thomas, who would later host the television series This Old House, lived intermittently on the tiny atoll of Satawal in the central Caroline Islands, an experience he documented in the book The Last Navigator: A Young Man, An Ancient Mariner, The Secrets of the Sea. While there, he lived with and studied under Mau Piailug, a master of the traditional Micronesian art and science of navigation, who had previously gained notoriety as the navigator on the early voyages of Hokule’a (which, as a Polynesian double canoe, was quite a different craft from the single-outrigger canoes of Micronesia to which he was accustomed).

A proa from Satawal (From the cover of The Last Navigator, by Steve Thomas)

The Last Navigator is a good book, an engaging, sensitively-written memoir of a young man attempting to learn about and fit into a very different society – in this case, one whose traditional, preindustrial culture was under extreme pressure from the forces of modernization and Westernization. While it contained what I suspect might be some valuable ethnographic observations and a good general description of traditional Micronesian methods of navigation (for a detailed explanation, see We, The Navigators: The Ancient Art of Landfinding in the Pacific, by David Lewis), it is scanty on information about the boats of Satawal and their construction.

Micronesia was home to a great number of outrigger canoe types – so great that James Hornell, in The Canoes of Polynesia, Fiji, and Micronesia, devoted many pages documenting separately those of the Carolines, the Marshalls, the Gilberts, the Marianas, and certain other of the region’s smaller groups and individual islands. Even within the central Carolines, there was too much variation between islands for it to be practical to document every differentiating detail, necessitating some generalization of a “western and central Caroline” type. Since I came to the subject of the central Carolines canoe by way of The Last Navigator, this post focuses, to the extent possible, on boats most like those that appear on Satawal, and relies on Hornell’s generalizations for a more encompassing view.

Flying proa or popo of the Caroline Islands. (From Hornell, after Paris) 

The ocean-voyaging canoes of Satawal are “flying proas” of a type which, according to Hornell, were called popos. Like almost all single-outrigger craft of the Pacific, they always sail with the outrigger to windward, using the outrigger float for stability in light or no air and as a counterbalance – supplemented by crew weight – against the force of higher winds. As such, popos are shunting craft, with identical ends that alternately serve as the bow and stern as the boat changes direction relative to the wind.

Notable differences in canoe design existed between the main island groups of Micronesia, as shown in this comparison of proas from the western and central Carolines (left) and the Marshall Islands (right). (Kubary)

Among the most distinctive characteristic of the popo are:

• a narrow, deep hull with identical ends but lateral asymmetry, in which the windward side is much less curved than the leeward. In fact, on some boats, the windward side of the hull is nearly a flat plane.
• hull construction of stitched planks on a dugout base
• a platform extending from the hull on the lee side, opposite the outrigger
• an oceanic lateen rig, consisting of a single triangular sprit sail hung from a mast stepped exactly amidships that pivots fore-and-aft with each shunt, allowing the sail’s direction and its center of effort to shift ends (not, however, without some complex evolutions on the part of the crew)

When Thomas lived on Satawal, Piailug was in the process of building a popo 33’ feet long and 8’ high from the keel to the “eyes” at the ends. This was the largest canoe built there in living memory, most others being around 26’ or 27’ long. According to Hornell, the canoes present in the central Carolines early in the twentieth century were smaller than those of the nineteenth, so lengths in the mid-thirty-foot range and, judging from Paris's drawings, even longer, may have been common in the past.

Hull Form and Construction

End, plan and section views of the Caroline proa (Hornell, after Paris)

On Yap, in the western Carolines, and a few other islands were large trees were available,

...all but the upper part of the sides and the two curved heads are hewn from a single log. In atolls where no large timber is available the dugout portion shrinks to a wedge-shaped piece channeled longitudinally on the upper side so as to give two everted edges upon which the garboard strakes are sewn.... Usually the shapes and sizes of the strake planks are irregular, suitable wood being too precious in atolls to permit either of long running lengths or of adzing opposite edges parallel. So the hull in these islands is a mass of patchwork, all, however, fitted together with remarkable accuracy. (Hornell)

Paris's plan and construction views on which Hornell's illustrations are based. (Source: Wikipedia. Thanks to Walter Stanish for uploading this version of the image and alerting me to it.)

According to Thomas, the hull timber was breadfruit or “a mahoganylike tree called rugger...” from which the keel was hewn and the planks were split. Thomas describes how a chainsaw was used to fell the tree for the keel of Piailug’s new boat. The chainsaw was a fairly unfamiliar tool on Satawal at the time, and few of the men knew how to use it. After the “blade-like legs” of the breadfruit were cut through and the tree was felled, limbed, and cut to its desired length, the log for the keel was 6’ in diameter and 30’ long. With the chainsaw, a couple of operators performed the process in one morning “what usually took six men more than a day” to perform with axes.

Thomas does not describe how planks were split or otherwise gotten out, but it is clear that adzes were used to shape all the timbers. The hull has two end pieces cut from solid timber, each of which attaches at an end of the keel and extends upward as a cutwater and stem “and ends throughout the western and central Carolines in a peculiar and most characteristic fork” (Hornell).

No plans or standard measuring devices are used in shaping the hull, the builders working instead by eye and by a series of proportions or ratios between various of the boat’s features. (For example: height of the mast equals length of the hull; length of the outrigger is one half the length of the hull. Thomas.) Regarding the pronounced asymmetry of the hull, Hornell explains that is counteracts the asymmetrical resistance imposed by the single outrigger, allowing the boat to travel straight with minimal steering input when the float is in the water.

Planks are added to the keel to build up the hull’s freeboard with, as Hornell says, “little or no need to fit strengthening frames and this is not the custom in the Carolines.... Adequate stiffness is obtained when necessary by the insertion of solid bulkheads or partitions beneath the transverse supports of the lee platform.” Stiffness is increased further with heavy thwarts and gunwales.

Thomas stated that Piailug, in building his new boat, lashed the planks together temporarily, but Thomas did not explain why. Perhaps it was not enough to ensure that each individual plank fitted properly against its neighbors but that, instead, the entire hull had to be test-assembled to ensure good fits. The wood of the cross-beams (i.e., thwarts) that Piailug wished to install was too tough to be worked with an adze, so the pieces were buried in moist sand for a period to soften them.

Planks are stitched to the keel and to each other with discontinuous stitches of coconut-fiber rope (i.e., coir), made, in Thomas’s account, by the island’s old men, hand-rolling the coconut fibers against their thighs. Planks were caulked with a compound of dehydrated breadfruit sap applied to strips of coconut husk. According to Thomas, this caulking gradually dries out and loses its efficacy, requiring the boats to be disassembled and rebuilt “every two years or so.”

During one of these rebuilding episodes on Satawal on a boat named Suntory (after a brand of Japanese whiskey), the builder in charge decided to lighten the boat to make it faster. After disassembly, all the planks were therefore adzed down to make them thinner. Thomas did not describe whether this process improved the boat’s performance or affected its strength or water-tightness.

Thomas agrees with Hornell in saying that the outer surface of the hull was finished very smooth, although the process of sanding or otherwise smoothing the planks it is not described by either. (Throughout much of the Pacific, shark skin was used as sandpaper for this purpose.) Hulls were traditionally painted in patterns of red, black, and white.

Outrigger and Lee Platform

According to Hornell, the two main outrigger booms, which are fairly straight, “pierce both washstrakes of the hull in large canoes and (extend) a few inches outboard on the lee side.” (In Hornell's version of Admiral Paris’s drawing, however, it is unclear if the booms are entirely surrounded by the washstrake or if, possibly, they are notched full-depth into its top surface). In the popo’s most characteristic form, the outrigger booms also serve as the main support for a large triangular platform which carries crew and cargo. Poles extend diagonally from the windward gunwale at points near both ends of the hull to the main booms near their outboard ends, and the resulting isosceles triangle is covered by planks or light poles.

A second rectangular platform extending from the hull’s leeward size further increases the boat’s cargo capacity. This platform is supported by another pair of heavy timbers that cross the hull. These timbers are angled sharply upward toward their outboard end, allowing the platform to remain dry with the boat at a significant angle of heel. Sometimes the surface of the platform is built directly on these sloping supports; on other cases, another, lighter framework is built over this main structure and decked over, creating a surface that is horizontal when the boat is on an even keel.

Enclosures of basketwork, which may be round, oval, or rectangular, often appear on one or both platforms. These are used primarily to protect cargo, but it appears they occasionally serve as shelters for passengers or off-duty crew.

Connection between the outrigger booms and the float. In the image on the left, the inner two crutches have been omitted for clarity. (Hornell)

The outrigger float, canoe-shaped in plan, hexagonal in section, and about half the length of the hull, is hewn from a solid baulk. It is connected to each boom by a pair of short crutches, the forks of which straddle the booms from below. The lower ends of these crutches are pointed and driven several inches into the upper facets of the float. Between each pair of crutch forks is a yoke which rests across the top surfaces of both booms and extends several inches beyond them. Holes are bored horizontally through the angled top surfaces of the float, and ropes are routed through these holes, over the ends of the yoke, and in a complex path around the crutches to hold the float securely to the booms, with the crutches in compression between them. Additional, lighter-weight braces are lashed to the undersides of the booms, further connecting them to each other and to the crutches, and from one pair of crutches to the other. The entire outrigger structure is thus highly complex and highly engineered for strength and flexibility.

Sail Rig and Steering

Caroline proas (Paris)

The defining characteristic of all true proas is the oceanic lateen or oceanic sprit sail hung from a pivoting mast stepped amidships. (I find the term “crab-claw” used often inappropriately, preferring to apply it only to sails whose leech is deeply concave and therefore somewhat reminiscent of the shape of a claw. This is not the case in the canoes of the central Carolines.) In combination with a double-ended hull, this permits the boat to be shunted, and sailed with either end forward. Sails were traditionally hand-woven from fibers stripped from the leaves of the pandanus or screw pine, but commercially manufactured cloth has apparently been in common use for some time.

Hornell takes pains to define the nomenclature of the sail’s spars, calling the one at the luff (the upper/forward edge) a yard, and the one at the foot a boom. He describes the rigging as follows:

A shroud runs from near the masthead to the yoke [i.e., the short, stout timber connecting the outrigger booms at their outer ends], to which it is secured after passing through a hole bored through its center. There is also a fore-and-aft running stay made fast respectively to the endmost thwart at each end of the hull.

(T)he sail is hoisted by a peak halyard attached far out on the yard and rove through a sheave hole in the masthead; the heel of the yard rests against a sail step set on a short thwart right in the bows, to which the tack is made fast.

There is no shroud or other line serving as such to leeward in this description, and in Thomas’s account of a voyage from Satawal to a nearby atoll, the rig was nearly lost once when the sail was backwinded, due to this lack of support on that side of the boat. No leeward shroud is shown in the diagram or cover photo of Thomas’s book, but in Paris’s diagram and one of his drawings (fifth and first images in this post), a shroud is visible leading from the masthead to the lee platform. Perhaps the practice varied on different islands even within the central Carolines.

Main features of a Satawal proa (from Thomas)

In the past, popos were generally steered by means of a quarter rudder with a tiller that extended laterally from its aft edge near the top. The rudder was not hung from the hull, but instead held by the helmsman’s foot against a wooden pin that projected from the hull. A rope from the top of the blade to the hull, visible in Paris's diagram (image #3), prevented loss of the rudder and perhaps provided some stability to it but apparently did little to hold it in its proper working position for, according to Hornell, “The steersman’s duty is the heaviest aboard and on a journey he has to be relieved frequently.” It rough seas when the rudder could not be controlled, it was lifted from the water, and several men with regular paddles would steer. In Thomas’s account, however, steering was always by means of a single steering paddle, and no rudder appears in his description or in the book’s diagram.

Canoe Houses

Caroline sailing canoes are built and kept in a canoe house. On Satawal, in Thomas’s account, each of the island’s eight clans owned a canoe and kept it in its own house. All the houses were on the same beach, near the main (only?) channel through the island’s surrounding reef, with the house belonging to the clan of the island’s chief directly opposite and closest to the channel. The canoe houses serve as social centers for the men, who typically gather there to talk and drink even when work is not under way on a canoe.

Experienced men of middle age do most of the work on the canoes, assisted and observed by younger ones -- or, in Thomas's account, those few younger ones who could be induced to take an interest any longer. Older men typically observe the work and offer suggestions but restrict their hands-on contribution to the making of rope.

Primary Sources:

Hornell, James, The Canoes of Polynesia, Fiji, and Micronesia, B.P. Bishop Museum, 1936, in Canoes of Oceania (with A.C. Haddon), B.P Bishop Museum, Honolulu, 1975

Kubary, J.S., Ethnographiphische Beiträge zur Kenntniss des Karolinen-Achipel, Leiden, 1889-95

Pâris, François-Edmond, Essai sur la construction navale des peuples extra-européens ou Collection des navires et pirogues construits par les habitants de l'Asie, de la Malaisie, du Grand Océan et de l'Amérique dessinés et mesurés pendant les voyages autour du monde de "l'Astrolabe", "la Favorite" et "l'Artémise")

Thomas, Steve, The Last Navigator: A Young Man, An Ancient Mariner, The Secrets of the Sea, International Marine, Camden, ME (no date). Originally published by Henry Holt, 1987

Additional sources, useful websites and pages:
http://www.samlow.com/screeningroom/navigators-filming.html
http://starrigging.blogspot.com/ and http://starrigging.blogspot.com/2017/06/canoe-sketch.html
http://waterworks-sysooke.blogspot.com/2011/10/chamorro-and-carolinian-sailing-canoes.html
http://archives.starbulletin.com/2008/04/25/features/story04.html
http://www.multihull.de/proa/history/p_history.htm
http://habele.blogspot.com/2017/03/historic-sail-showcases-micronesian.html
http://www.samlow.com/sail-nav/CEREMONY.htm
http://proafile.com/multihull-boats/article/the-proa-file-primer

Philippine Bangkas - More Design and Construction Details

In our previous post, we looked at details of outrigger design and construction in the Filipino outrigger boats known as bangkas. Here we'll look at other design and construction details in additional images from Michael Williams of Flatwolf Photography, to whom we express our thanks. (Click any image to enlarge.)

Bangkas were originally built as dugout canoes, then as extended dugouts (i.e., with strakes added atop the dugout base to increase freeboard). As shown in this bangka undergoing repairs, plywood construction is now more common. The bottom remains a heavy plank -- perhaps a bare artifact of the original dugout concept. A roughly-hewn stem is scarfed onto the bottom, but perhaps it will be fined up before the missing side planking is replaced. Straight frames support the sides. Not visible here, but shown in the previous post (3rd image from top): there are no frames across the bottom; the side frames merely butt against the top of the bottom plank.

Some larger bangkas have a sharply flaring top strake. This would widen the top of the hull for more interior room, deflect spray, and increase buoyancy if the bow plunges in rough seas.
The outrigger booms show both similarities and differences from that on another large commercial passenger bangka shown in the previous post (6th from top). The forward boom consists of an open-top box beam making up about half of the boom's total length. Inside the box are five bamboo poles, two above three, all of which extend beyond the box. The bottom three poles extend farther than the top two and connect directly to the outrigger float. The next boom back lacks the box beam, and has the poles supported across their middle lengths by what might be a flat plank or possibly additional shorter poles.
It's unclear if the nicely shaped outrigger float is a solid carved timber or -- what we think more likely -- a hollow plywood or composite construction.

The flaring top strakes on this this bangka dive boat extend into a long, overhanging bow that supports a flat platform.

A bangka of similar size to the one above lacks the flaring top strake, and its long, extended bow is narrow and not intended for use as a platform.

This small bangka has an elegantly vertical sternpost.

In contrast, these small power bangkas have steeply sloped sternposts.
The running gear is of notably light weight and entirely exposed, requiring great care when operating in shallow water and when hauling the boat onto the beach. The rudder post is secured outboard to starboard and is turned by a short tiller connected to a push-pull rod, allowing the helmsman to sit forward of the engine box.

Philippine Bangka Outrigger and Boom Variations

The bangka -- also known as banca and paraw -- is a double-outrigger boat ubiquitous in the Philippines. According to one online dictionary of Tagalog (an Austronesian language, one of the more commonly spoken languages of the Philippines), the word bangka simply means "boat," and this appears to be accurate and logical, given the great diversity in bangka configurations.

Indeed, there seem to be only two or three common features of bangkas: their main hulls are always narrow; they are always double-ended; and they almost always have two outriggers. Their differences, however, are manifold, including variations in materials, construction methods, most aspects of hull shape, houses, internal arrangements, overall size, propulsion, decoration, and usage. They're sometimes called the "Jeeps of the sea" because they are supposed to be able to do everything, but they do everything not necessarily because they are versatile, per se, but because there's a different style of bangka for nearly every possible application. 

We've written about bangkas several times already, but an offer of photos from reader Michael Williams of Flatwolf Photography has given us a good reason to look at them yet again. What strikes us most about the current batch of images is the variation in the configuration of outrigger booms. As always, click any image to enlarge.

We'll begin with this image of a medium-size power bangka as a kind of baseline for comparison. The outrigger float -- a single bamboo pole of large diameter -- angles fairly steeply up toward the bow. To achieve this, forward boom slopes down quite gently, while the aft boom takes an abrupt turn downward. One finds these two boom configurations in different combinations on different bangkas.

Three booms with progressively steep ends to accommodate the sloping floats. The booms are stout and rectangular in section. Round poles lashed atop them do not seem to add much, if any, strength.

The boom in this small paddling bangka is fastened with lashings to a cleat that spans between two frames about halfway between the gunwales and the bottom of the interior. The frames themselves extend above the gunwales, providing stops that prevent the boom-and-float assembly from shifting forward or aft.

The booms to the right and left of the image are straight across the middle, while the boom in the middle is bent down somewhat amidship, for a bit of a gull-wing configuration. The booms appear to be built up of three sections, the joints visible where the horizontal section transitions to a downward curve toward the float. The joints are probably simple scarf joints, lashed with cordage and covered with some kind of sealant or adhesive. 

These light, obviously very flexible booms in this nicely finished, small power bangka appear to be in one piece, although they might be scarfed together as in the previous photo but finished more carefully. The booms are placed outboard of the extended frame tops. In comparison, the booms on the boat in the third photo were placed inboard the extended frame tops.

The five booms on this large passenger bangka are complex structures. Amidships, each appears to be an open-topped, box-section girder from which a tapered, rectangular-section beam protrudes outboard with a slight downward slope. Lashed on top of these are several bamboo poles, lashed together and extending further outboard. One pole in this bundle extends even further outboard and curves downward to contact the float, which is itself a few bamboo poles of small diameter, providing probably only modest buoyancy. In the main, the booms appear to be quite rigid, although the lightness of the final outboard section may impart some flexibility.

A single-outrigger bangka. This appears to be by design, and not a partially disassembled boat. The float is a carved piece of timber, not a bamboo pole as in most other examples. The amount of flexibility in the construction appears to be minimal.

The outriggers on this small paddling bangka tilt downward toward the bow. We can't think of a good reason for this unusual design feature.

The Yathra Dhoni - A Single-Outrigger Ship of Sri Lanka

The large vessel is a yathra dhoni. Its outrigger allows it to sit upright on the beach without temporary supports (from Devendra, "The Lost Ships of Lanka.") (Click any image to enlarge)

Seagoing ships with outriggers are a rarity. If one defines “ships” as “(floating mobile nautical) structures which constituted significant elements in the economies of the societies which built and operated them” (Basil Greenhill, in The Earliest Ships: The Evolution of Boats into Ships), then a few of the larger traditional single-outrigger canoes of Oceania would qualify, but based on their size, burthen, and the fact that they are “canoes,” most modern observers would still call them “boats” without hesitation. Some motorized bancas of the Philippines might be (just) large enough to be thought ship-like by some, but no one of these double-outrigger vessels would qualify on the grounds of economic significance.

The yathra dhoni of Sri Lanka and the Coromandel Coast on India, then, may be the only traditional outrigger vessel that was undeniably a “ship.” Large and burthensome enough so as not to be mistaken for a boat, and used as a cargo carrier on both coastal and short oceanic voyages, the single-outrigger yathra dhoni (also spelled yatra dhoni, and also known as the maha-oruwa or maha oru, meaning “big outrigger canoe”) was in use for centuries – possibly thousands of years – and remained in common use into the early twentieth century.

Admiral Paris's drawing of a yathra dhoni (from Essai sur la construction navale des peuples extra-européens ou Collection des navires et pirogues construits par les habitants de l'Asie, de la Malaisie, du Grand Océan et de l'Amérique dessinés et mesurés pendant les voyages autour du monde de "l'Astrolabe", "la Favorite" et "l'Artémise")

Outrigger ships in Sri Lanka were noted by Strabo (65 BCE-19 CE) and Pliny (23-79 CE), and if these were not yathra dhonies per se, they were probably their direct ancestors. A temple carving in Borobudur, Java, dated to the 8th to 10th century CE, shows “the arrival of Aryan emigrants to the Indonesian Islands” (Vitharana) in an outrigger vessel with features similar to the yathra. (The original Aryans, however, were from the area that is now northern India, not Coromandel or Sri Lanka.) Near the end of their history, yathras were known to be trading as far as the Moluccas, so their earlier use transporting Aryans or their neighbors to Java (which, like the Moluccas, is in Indonesia, but closer to India) seems credible.

Most yathras were 50 to 60 feet LOA with a main hull beam of 12 to 15 feet. The largest were 100 feet long with a 20 foot hull beam. Vitharana states that they were 10 to 15 feet in height, although it is unclear what points of measurement are implied. Cargoes ranged from 25 to 75 tonnes, with 50 being typical. The main hull was double-ended, with slack bilges, full midsections, and a slightly hollow entry.

Tom Vosmer's profile drawing of the Dodanduva yathra dhoni model (from Devendra, "The Lost Ships of Lanka)

The outrigger varied in length, from about a third (Paris) to well over two-thirds (Vosmer’s drawing of a highly detailed model built in the former yathra center of Dodanduva, Sri Lanka, that is widely accepted for its authority) the length of the main hull. It was always mounted on the port side, fastened directly to substantial, downward-curving booms that extended right through the main hull at the level of the deck beams. (One simplified model exists with the outrigger to starboard, but this model lacks a rudder and may represent a different vessel type, or the difference may be due to imprecision on the modeler’s part.) Guys leading diagonally from the main hull to the outer ends of the outrigger booms helped stabilize the outrigger float fore-and-aft.

The Dodanduva model of a yathra dhoni (from Green) 

The yathra’s rudder followed the curve of the sternpost. The rudder on the Dodanduva model is enormous and wide, but other reliable sources show rudders of more graceful shape and conventional proportions. From this, it appears that rudders were fitted in a range of sizes and styles. Vitharana refers to a “secondary rudder to act as a leeboard … in the region of the main mast touching the water on the starboard side,” but in no models or drawings that I know of does such a feature appear. A leeboard would appear to be unnecessary, since the hull was built on a keel that provided significant lateral plane to resist leeway. Some models and drawings also show a “gripe” at the bow and a skeg at the stern (upon which the rudder’s lower end was hung), both of which added to the lateral plane and directional stability.

Hornell's sketch of a yathra dhoni

The common rig was a ketch with square headed, loose-footed cloth lugsails and a jib on a bowsprit, said by Green to be “a rig common to the region of the Indian subcontinent.” Some smaller yathras may have had a single mast. Hornell’s sketch of the ketch version shows a second headsail inside the first one, apparently set flying, with its tack led to the port bulwark or possibly to the foredeck. Admiral Paris’s drawing shows a whisker pole holding out the luff of the mainsail. Standing rigging included shrouds, fore- and backstays, and a stay between the mastheads. According to Green, “The arrangement of the halyards was such that they prevent the mizzen yard from passing around the forward side of the mast. It must therefore be concluded that the mizzen sail on the yatra was never tacked, but went aback against the mast when occasionally on a starboard tack.”

Two bulkheads divided the hull into three sections: small bow and stern compartments, the use of which I have not found described, and a large cargo hold between them. Much of the deck was covered by a light, removable deckhouse roofed with split bamboo, leaving only narrow walkways along the sides for the crew to move fore and aft. Sliding cargo hatches were offset to starboard, and a simple cargo handling crane was located to port. In order for this to come in use, lighters – probably small dugout canoes – must have come alongside the main hull between the outrigger booms. But because the vessel would sit upright on a beach, supported by the outrigger, it may be that loading and unloading was often done on land. One assumes that the deckhouse roof was removed before cargo was handled.

The hull of the yathra was of a carvel construction using an unusual combination of stitched and nailed fastening. The planks, a minimum of 2” thick, were stitched to each other with coir rope and nailed to the frames with iron nails and roves. Accounts differ on whether the stitching holes penetrated straight through to the inner surface of the planks or exited on the plank edges. In any case, it is clear that the stitching served only to hold the planks against each other and not to the frames. Details on the order of construction are lacking, but one presumes that the planks were stitched first to make them tight, and nailed second. Joints were caulked with coconut husks and leaves inserted before the stitches were drawn tight.

Vosmer's construction drawings of the Dodanduva yathra dhoni model (from Devendra, "Pre-Modern Sri Lankan Ships")

Stem and sternpost were fastened to the keel with hooked scarfs held with locking wedges. The frames and deck beams were few in number and widely spaced but of heavy scantlings, providing sufficient overall strength. Deck beams extended through the planking on both sides. Green says the frames were continuous from sheer to sheer, but given their scantlings and the hull’s shape, this seems impossible. Perhaps his information, which is not footnoted, stems from observation of a model which used continuous frames for expediency.

Tom Vosmer took careful measurements of the Dodanduva model, fed the details into a hydrostatics program, and found that the main hull, even without the outrigger, was “reasonably stable.” The outrigger, of course, significantly increased the vessel’s righting moment (by a factor of 100). It also increased drag, and therefore, the ship’s powering requirements. The rig, therefore, could have been smaller and simpler if the (still seaworthy) hull did not have an outrigger attached.

Yathra dhoni at anchor in Kalpitiya, Sri Lanka, 1913 (from Devendra, "The Lost Ships of Lanka") 

Yathras were mainly short- and medium-haul cargo vessels, serving ports large and small throughout Sri Lanka and the Coromandel Coast and making regular voyages to the Maldives (550 miles from Colombo, Sri Lanka), although they also sailed at least occasionally to the Moluccas (3,600 miles). Typical cargoes included textiles, rice, salt, fish and fish products, tea, and tiles. A large one carried a crew of 18.

The outrigger was always kept to windward except, perhaps, in the most benign conditions – an unusual and highly limiting practice for a tacking single-outrigger vessel. Working within these limits required coastal voyages to make use of the daily reversal of land and sea breezes: the vessel sailed only during the part of day when the prevailing breeze allowed the outrigger to be kept to windward. On longer voyages, the monsoon breeze dictated direction. This would have meant just a single round trip from Sri Lanka to the Maldives in any given year, whereas a vessel that could sail with either side to windward would be able to make several round trip voyages of that distance each year.

Most accounts tell of the yathra succumbing to competition from steamships around the turn of the twentieth century. Vitharana claims that 40 of them were still serving Dodanduva in the 1930s, but all other accounts tell of the last one being built there to some fanfare in 1930; that is was wrecked on its first voyage in the Maldives; and that that was the end of the tradition.

Sources:

Somasiri Devendra, "Pre-Modern Sri Lankan Ships" in Ships and the Development of Maritime Technology in the Indian Ocean, David Parkin gand Ruth Barnes, editors. Routledge, 2002

Devendra, "The Lost Ships of Lanka," from Maritime Heritage of Lanka: Ancient ports and harbours. National Heritage Trust Sri Lanka, 2013

Devendra, "The Mansion of the Sea," The Island Online - Saturday Magazine
Jeremy Green, "The archaeological contribute to the knowledge of the extra-European shipbuilding at the time of the Medieval and Modern Iberian-Atlantic tradition" Proceedings: International Symposium on Archaeology of Medieval and Modern Ships of Iberian-Atlantic Tradition

James Hornell, Water Transport: Origins and Early Evolution, Cambridge University Press, 1946

The National Trust of Sri Lanka, "The Annapoorani and The Amugoda Oruwa: The Forgotten Ships of Lanka" on Facebook

Corioli Souter, "Travellers and Traders in the Indian Ocean World Curatorial Audio Guide," WAM Audio Tours, Western Austrian Museum

Vini Vitharana, "The ORU & the YATRA" Nautical Archaeological Society, 1992, republished 2012

Vatican boat model exhibit, Part 2

In a current temporary exhibit at the Vatican Museums, dozens of models of watercraft from numerous nations and cultures are presented to represent the diversity and interconnectedness of humanity. (See our previous post on this exhibit.) The models are displayed in glass cases (hence the poor quality of the photos that follow) with little explanatory material. 

We present our photos with the scanty information from the exhibit cards in quotation marks, and our own brief observations in parentheses. We invite readers to contribute additional information about any boat in the Comments. Only models representing craft from "outside the Western tradition" are included here. More images of other models from the exhibit will follow in a subsequent post. As always, click any image to enlarge.

"Japan: Sailing boat" (looks like it would be highly capable in surf)

"Indonesia: Sailing boat with outrigger" -- (actually two outriggers. Although the rig is set as a square sail, it appears to be hung asymmetrically on the mast and can probably be canted to form a kind of lugsail.)

"Philippines: Sailing boat with outrigger" -- (again, two outriggers. This is a banca, with a Western-style sailing rig.)

"Sri Lanka: Boat with fisherman" (We wonder if the model attempts to represent any real type of boat, or if it is purely fanciful, its shape dictated by the material available to the modeler. What's surprising and touching about this model is the paddler, who is modeled with a great deal of humanity.)

"India: Pirogue with rowers" (paddlers, actually)

"China: Boat for recreation" (and by that, we mean eating, drinking and sex.)

(background) "India: Pirogue with rowers" (again, paddlers in fact)

"Thailand: Royal boat" (identical exhibit cards for both models)

"China: Sea Junk" (The truncated bow and minimal rig are fascinating aspects of this model, which is certainly not meant to be an accurate representation.)

"Southeast Asia: River boat" (a sampan)

"China: Sea Junk with three masts"

"China: River boat"

"China: Dragon boat for racing"

(Nationality not identified)
Back row:
Left: "Raft for fishing with cormorants"
Center: "Houseboat with passenger and boatmen" (Error in labeling, as this open craft is clearly not a houseboat. The Italian label identifies it as a sampan with a passenger and a boatman)
Right: (label illegible in photo)

Front row: 

Left: "Houseboat with coxswain"
Center: "Houseboat with passenger and boatmen" (Error in labeling, as this open craft is clearly not a houseboat. The Italian label identifies it as a sampan with a passenger and a boatman)
Right: "Houseboat with fisherman"

"Samoa: Seven paddle canoe" (Noticeable similarities to a Samoan canoe in our post about Buckminster Fuller's model collection)