When the Royal Navy was still doing boarding actions they used cutlasses, roughly 36" (slightly wider than a door, which was why Midshipmen were told not to run around with them in their mouths). Able to cut & thrust. Or Boarding Dirks (Long Daggers).
Why weren't they tempted to take the captured ships as war prizes to aid in the later fights? At the very least they should have placed scuttling charges on the power core to prevent it from being recaptured and used against them. Maybe pick up some rifles, sidearms, and grenades for the inevitable just in case scenario? They wouldn't have weighed them down much.
