Panabas

[Bill]

Nice. Looks like the prong got bent in the wrong direction.
Cato suggests the prong was to distract the opponent by raking against a exposed part of the body. While this may be true in combat, I doubt it was the main purpose or often used that way.
He also states many examples of kampilans have broken or bent prongs.
He also states that the kampilans were a arsenal weapon of a wealthy datu as well a arsenal weapon for the crews of a prahus (fighting ship).
Now close combat & lack of shields (no room on ships) makes the kampilan an unlikely sea weapon; except for the feature found on your panabas.
The concave area, the 2 "nubs" & prong would be ideal for grabbing the side of another ship for boarding. The nubs for a slight indention into the wood & the prong to pull (may explain why so many are damaged).
The opposite is true also, the prong could be used for pushing another boat away.
On land, the kamplians prong area is ideal for grasping & pulling down a shield, an easy experiment will prove this.
The "saw" like substitute, on some kamplians, would provide similar results on both land & sea.
So I'll speculate that your panabas is weapon used at sea in a fighting ship, likely a arsenal weapon of the ship.