Rodney's torpedo-defence water and the jet-ski suggestion

Did water discharged through Rodney's stern increase her speed?

No. The reply instead recalls, with some uncertainty, that the commander in question never filled Rodney's torpedo defences with water.

The suggestion that stern discharge could turn Rodney into a giant jet ski receives a direct rejection. The accompanying point is a qualified recollection that the commander in question never filled her torpedo defences with water.