As C W F Hamilton of New Zealand, (some like to think of him as the "father of the Marine Jet) found out whilst experimenting with early jet boats there was a dramatic increase in boat speed when the jet outlet was lifted out of the water and exited to atmosphere. Newton's laws action / reaction! (Some used to think the jet pushed on the water!!)
What I am getting to is where could a jet be fitted into a H C so it could exit to atmosphere?