Lowers CG, plus it just wouldn't be a BeachBot if an FP were high off the ground.
Every FP that has been on a 330 machine has been close-ish to the ground. Winches low down, arm power sources low down, I can't think of a single FP that made it higher than 2' from the ground on a 330 machine (except maybe in 2009).
It also gives a good chance to get extra reductions via chain and sprocket.
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Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons
"Rockets are tricky..."--Elon Musk
