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.