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Friday, April 7, 2017

The Vattai of Tamil Nadu

Examples of traditional frame-first boat construction in Asian cultures are rare. Throughout the Far East, Middle East and east Africa, shell-first construction of planked boats is the norm, where it is used for everything from sampans and junks to dhows. One of the few exceptions is the vattai, an open, sail-powered, flush-planked (carvel) fishing boat common in the state of Tamil Nadu, in India’s southeast.

A vattai in Tamil Nadu
A vattai in Tamil Nadu. Source: Blue (click any image to enlarge)
The vattai is described by Lucy Blue in “The Historical Context of the Construction of the Vattai Fishing Boat and Related Frame-First Vessels of Tamil Nadu and Beyond,” published in Ships and the Development of Maritime Technology in the Indian Ocean (David Parkin and Ruth Barnes, editors; Routledge, 2016). The information and images in this post are from that article.

To quote Dr. Blue:
"Vattai, are flat-bottomed, have a box-like transverse section and are near wall-sided over much of their length. They range in size from around 13.72m long, with a beam of 2.13m and a depth of 1.37m, to the smallest vessels of c. 5.18m x 1.07m x 0.76m. However, irrespective of their size, they are all similar in shape with very high bows, and two or three masts each with a settee-lateen sail, a balance board, and, uniquely on this coast, leeboards."
The design process is of much interest. A single mould form or template is used to lay out most of the frames on a scrieve board, the form being flipped to draw the port and starboard half-breadths. (Forms for different boats differ from one another, apparently, only in the radius of the curve that joins their two straight, right-angled legs.) Since the boat’s cross-section (half-breadth shape) is constant across its entire midbody, a single shape drawn on the scrieve board suffices to define most of the frames, and this follows the exact shape of the form laid square to the edges of the scrieve board.

Use of mould form and scrieve board to design a vattai boat
Use of the mould form and scrieve board (A) to create the shapes of the "equal" frames for the midbody (B,C,D), and the progressively narrower frames toward the ends (E, F, G). 
Fore and aft of the “equal” frames that constitute the midbody, each of the next three progressively narrower frames at the bow has an identical counterpart in the stern. These frames that define the ends are derived from the same mould form according to a formula that defines how far in from the scrieve board’s upper edge and how far up along the diagonal the form is placed. By rotating and raising the form, different frame shapes may be drawn to create the narrowing and flare of the hull’s ends. The final three frames in the very bow and stern, however, are not drawn or gotten out at this time.

In the boat recorded by Blue, there were 15 “equal” frames for the midbody plus 12 “unequal” ones, evenly divided between the bow and stern. The midsection always consists of an odd number of frames – the central master frame, and equal numbers of identical frames fore and aft of it. The design can be readily made longer by the addition of more equal frames in the midbody with no changes to the ends, and made wider starting with a wider scrieve board but using the same mould form. Rules of thumb establish ratios between length, breadth, depth, and frame spacing, so the builder’s discretion to make changes is limited mainly to his choice of the mould form and number of frames.

Vattai construction drawing
Vattai construction drawing
Frames are built up from floor timbers and futtocks, which are assembled with “a complex dovetail joint” that “extends right through the turn of the bilge.” The vattai has no backbone, so apparently the frames are set up on the straight, flat bottom planking, which must be laid down first. Stem and sternpost are butted with a lap joint against the ends of the central bottom plank. The article states variously that the shapes of the very ends are determined by battens (ribbands) or by laid planking between the midbody frames and the end posts. Whichever is truly the case, these define the shapes of the three final pairs of half-frames at each end. Only in these final three sets of frames do the shapes of the vattai’s bow and stern differ. They are installed without floors, their lower ends overlapping fore-and-aft where they land on top of, or are notched onto, the stem and sternpost. (This detail can’t be determined from the drawing.)

I have been unable to find any other photos, descriptions or even references to the vattai through Google searches and would welcome additional input. There is much else I’d like to know, including:
  • whether the planks have a caulking bevel, and the materials (if any) used for caulking
  • the design process for the end profiles (i.e., whether the stem and sternpost shapes are determined by template or drawn by eye.) 
  • details of the rig and leeboards
  • details of usage: crew size, responsibilities, sailing procedures and performance

I would also much like to see additional photos. Google image searches for terms like “fishing boat Tamil Nadu” yield a number of stock photos of open fishing boats that do not appear much like the vattai (the distinctive bow shape is an easily-noticed identifying characteristic), and nothing else even close. Please communicate in the comments if you can add to the discussion.

Thursday, March 23, 2017

Bundle Boats in Oman and Elsewhere

In the last week or so, two bundle boats from Oman came to my attention. First, a reader sent me a link to this travel article in Daily Kos, containing this photo:
Mangrove root bundle boat, Oman
Caption from original article: "This old, traditional, fishing boat is made from “barasti”, the aerial roots of the mangrove.  I took this shot on the beach near Sohar, the third largest city in the country located near the UAE border." (Click any image to enlarge.)
This brought to mind the following photo of a shasha, another Omani bundle boat, from Tim Severin’s The Sinbad Voyage, which I reproduced in a post several years ago. But unlike the boat in the Daily Kos photo, this one was made from palm fronds.
palm frond bundle boat, Oman
A shasha -- an Omani bundle boat made of palm fronds (Source: The Sinbad Voyage)
The very next day, an image of another Omani bundle boat, also apparently made of palm fronds, appeared in my Facebook feed. I found it surprising that, even in the present day and within the confines of a rather small country, two methods of bundle boat construction, based on different materials, remain in use.
palm frond bundle boats, Oman
Original caption: "These are fishing boats in Oman. They are filled with polystyrene and paddled out to sea. At night the catch is landed and the village builds bonfires to cook supper. Which is fish." (Posted by Jonathan Savill to the Facebook page Church of the Double-Bladed Paddle)

Bundle boats are not really boats: they are boat-shaped rafts that derive their buoyancy from the materials of their construction, which are themselves buoyant. In contrast, true boats achieve buoyancy enclosing air within a watertight shell (or, to phrase it another way, by excluding water from a watertight shell).

In most cases, bundle boats are made from soft, flexible materials like grass, rushes, reeds, or leaves, large amounts of which are wrapped with cordage into long bundles – generally pointed at both ends – and then tied to other bundles into a boat shape – i.e., pointed at the bow (and often, at the stern), and usually with something approximating either raised gunwales, also composed of bundles, or a cockpit formed by leaving a cavity in or between bundles.

Sticks, roots or branches may also be used for construction. In most cases, these are tied into bundles in a manner similar to that used for soft, flexible materials, but in others, they are arranged and lashed side-by-side and not truly bundled. This method reduces the craft’s buoyancy and freeboard, also reducing its payload and leaving the boatman’s bottom constantly wet, but it also reduces its weight and makes it easier to dry, probably prolonging its life.
ambatch bundle canoe, Upper Nile
A canoe-like bundle boat used on the Upper Nile by the Dinka and Shulluk people. In this example, ambatch branches are tied into bundles, then the bundles are tied to each other into a boat shape. Indigenous to parts of Africa, ambatch is a  large shrub or small tree with a lightweight wood. (Source: Hornell)
ambatch bundle boat, Angola
An ambatch canoe on Lobito Bay, Angola. In this example, the branches are not truly bundled, but are lashed side-by-side into a boat shape. This photo and the one above it are from Hornell's 1946 work, Water Transport: Origins and Early Evolution. I don't know if such craft are still in use.
Absent gunwales or a cockpit, a bundle-built craft would have no “inside,” and lacking this characteristic, it would be a stretch to to call it boat-like. But that’s hardly a firm definition. Some models of papyrus bundle craft from ancient Egypt lack “insides” but are so boat-like in shape that it is hard to deny them the name bundle boat. (The models do have very low bundle-built toe-rails, however, which approximate the function of gunwales in a minimal way.)
Egyptian reed fishing boat model
Ancient Egyptian papyrus-bundle canoes pulling a trawl between them. (Source: Hornell)
Somewhat similar reed “boats” remain in use on Lake Titicaca, although they have substantial bundle gunwales, and thus a definite “inside.” What most distinguishes these craft from Egypt and Lake Titicaca from the Omani, Upper Nile and Lobito Bay types shown above, however, is the large volume of the bundles in comparison to the load, placing the boatman and his cargo well above the water and giving fair promise of keeping him and his cargo dry.
Reed balsa boat, Lake Titicacas
A fishing balsa made of totora reeds, on Lake Titicaca (Source: Hornell)
The bundle boat was an technological dead end in the sense that it apparently never evolved anywhere into a true boat. Although stick-built bundle boats appear superficially to be a step in that direction, they are still solidly rafts in concept.

But technological evolution is not the sole measure of past or present validity. The fact that bundle boats remain in use in more than one culture in the 21st century testifies to their practicality and the soundness of the concept. 

Sources: 
Basil Greenhill, Archaeology of the Boat
Paul Johnstone (Ed., Sean McGrail), The Sea-Craft of Prehistory
James Hornell, Water Transport: Origins and Early Evolution
(and as noted in text)

Friday, March 10, 2017

Bronze Age Carpow Logboat Moves to Permanent Home in Perth

We haven't had time for a post lately, so to keep the pump primed, we'll bring this recent news item to your attention, courtesy of The Courier.

The Carpow boat, a 3,000-year-old logboat excavated in 2006 from the River Tay in Scotland, was recently moved to a permanent home at the Perth Museum and Art Gallery. The 9.25-meter-long boat was recovered in generally very good condition, and it includes the transom board that closed in the stern. It is the second oldest logboat discovered in Scotland. Sadly, much of the bow is missing, but it is still one of the best-preserved Bronze Age logboats in Britain. This short video summarizes the excavation.



This next video shows the boat after conservation. The transom board is not in place, but you can clearly see the bosses that held it there, which were left standing on the inner surface of the boat when the trunk was carved out.