An instrumentation rake assembly comprises a rake tower capped at an immersed end and mated to a lead carrier at a base end. The rake tower comprises a curved wall oriented along a longitudinal axis and supporting a plurality of probe holders. The curved wall has an inner surface defining an internal passage for carrying instrumentation from the probe holders to the lead carrier. In another aspect, an instrumentation rake assembly comprises a plurality of rake towers, each having a base end and an immersed end, and each rake tower being coupled at its immersed end to one or more other rake towers.