Friday, September 15, 2017

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.

Philippine bangka boat - photo by Michael Williams
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.
Philippine bangka boat - photo by Michael Williams
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.

Philippine bangka boat - photo by Michael Williams
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.
Philippine bangka boat - photo by Michael Williams
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. 
Philippine bangka boat - photo by Michael Williams
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.
Philippine bangka boat - photo by Michael Williams
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.
Philippine bangka boat - photo by Michael Williams
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.
Philippine bangka boat - photo by Michael Williams
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.


  1. Hi Robert,

    Great post! And area of interested is the variation.

    Wonder if the guy in the last photo is paddling his boat backwards?

    One interesting variation is on some interisland moderate size bangka that steel drums are lashed on top of the booms.

    The stability depends on the crew and cargo being central. The outriggers (katig locally) rely on very light sinking loads.

    So if crew or gear moves off centre then the boat has growing stability until the katig are underwater (only need to be pushed down a foot) and then there is no additional stability to be found.

    This doesn't make the boats dangerous!

    Unless cement bags or people are stacked on the roof or move off centre in the main hull.

    Happily the hulls are designed nicely to keep everything central.

    I had a couple of articles on Philippine boats.

  2. Oh .. forgot my Photo.

    Please feel free to use anything with acknowledgement.

    This shows a bangka with empty drums to give more buoyancy if the boat starts heeling excessively. There's about 400kg or around 900lbs of buoyancy per side.

  3. Mike -- Many thanks for this input. I had not seen the use of steel drums for added buoyancy on bangka outriggers before.
    Regarding the small bangka with the outrigger floats angled the "wrong" way -- I considered the possibility that the boat was being paddled backwards, but the shapes of the stem and sternpost make me think otherwise. Here's another speculation: perhaps the entire outrigger assembly was removed as a unit for some reason (e.g., boat storage, maintenance), and then reattached backwards.
    Your blog is great! Plenty of interesting articles there about the kinds of boats we like. I can't figure out how to subscribe to it. Please let us know. Thanks again.

  4. Excellent essay, as usual. I wonder also, if the flatter forward cross-beam in the first photo is the strongest configuration in that part of the outriggers most subject to stress. So, you get two things, strength and an reduction of a nose-diving ama.

  5. I joined Carlos Solanilla for the 2009 Everglades Challenge aboard his 21 foot "paraw" like outrigger canoe. He used a skinny proa center hull with two 5 inch diameter, 20 foot long bamboo amas, with curved cross-beams like a paraw. I was struck by the fact that I could push these bamboo amas underwater with my foot, but while sailing I was aware of no bad habits or surprises (though we did have light air).

    1. I have also noticed that they can be submerged quite easily by foot, then it occurred to me while they are moving they provide some buoyancy but also act as a bit of a wing, providing lift, thereby increasing buoyancy.

  6. Hi friend!
    I'm looking for plans for a 20 and 50 foot bangka. Can you indicate any?