Equalizer
Currently, the best way to use cannons seems to be to ram the enemy ship. It is not clear whether cannons are still weaker than lasers when used in this way.
But it mean that you have cannon wall fast enough to ram enemy before he kill your CR or cut you in half, best way for laser wall (mostly with triangle shape) is to kite while cannon shells never reach it while laser easily kill enemy.
So wall can ram and kill laser wall only if laser wall cannot kite fast enough (as seen on tourney).