I am using a Desert Star Sport model pinger 
http://www.desertstar.com/newsite/sport/sportscout.html.  As part of my NOP, I turn on this pinger so that in an emergency, a diver could home in on my submerged location. It was operating this weekend.   As to forward sonar, I would love to have it but currently don't.  This year, sub play money went to buy the OTS underwater communication gear.  May be next year, I will add the sonar.  You have any recommendations?