When I was designing and building my boat, I always enjoyed when other psubbers gave report on their psub dives. As such, below is an executive summary of a recent dive of my boat.
Dive long, R300 July 14, 2010
On Wednesday July 14, 2010, the R300 was transported to Medina Lake, Plum Cove in south Texas to test some new equipment that I had installed in the boat since my last dive in February. Specifically, I had installed new OTS underwater comms and a new VHF marine radio I got from Alec (thanks!). Also I install new sensors that enabled me to know the location of all my control surfaces. The new VHF radio worked great. The VHF radio was so strong that I was able to use the radio while being submerged and sitting on the bottom at about 10 foot. The OTS underwater communication gear worked great as well. It was very nice to be able to communicate with the surface station while being submerged. I need to go back and do some more training with the radio as I kept inadvertently getting into the menu mode. The range of the OTS gear according to the manufacturer is 1000m. On this dive, I did not get a chance to confirm this. I wired the VHF and OTS gear according to the wiring diagram that is posted at the Psub.org web site. For future dives, I need to do some training on the menu system. Also I am looking into wiring the boom mike and headset so that both the VHF and OTS comms share the same headset, and I use a switch to select UWC vs SC.
My new control surface sensors worked great. I use the measurements to send the control surfaces back to a neutral position when the joy stick or rudder pedals are centralized. This is helpful on this boat as the pilot can not see any of the control surfaces.
During the dive, we were able to successfully execute a simulated rescue of a downed sub. The divers were able to locate the sub in about 9 ft of water and attach a safety line from the boat to the surface buoy in about 20 minutes even though the water visibility was poor at about 4 ft. After that, it took another 15 minutes for them the surface the boat manually by adding air from a spare scuba tank with a whip. The Desert Star receiver has two settings, high and low. The divers found that the high setting was pegging on each ping regardless of where the receiver was pointed. The low setting worked fine. By rotating in the water column, they could see in which direction the signal was strongest and move in that direction until they found the boat. On future dives I will try and find the max range of the unit.
On the down side, during one of the dives, the boat surfaced near the shore and when the pilot attempted to maneuver away from the shore, the rudder control arm again broke even though I had beefed up the weld on the control arm. Since the dive, I have replaced the steel control arm pin with an aluminum shear pin with the hope that if the rudder gets into a bind, this pin will shear rather than tearing off the control arm and we can recover without terminating the dive. This terminated further submerged maneuvering test for day.
We made and interesting discovery concerning the emergency beacon and the OTS gear. The OTS gear transmits and receive on channel one at 32.768U kHz while the emergency beacon (Sport by Desert Star) transmits and receives at 72.5kHz. Even though these devices operate at different frequencies, we found that during the dive, the OTS surface receiver picked up the pinging from the emergency beacon. This may be because the transponders for both units are hard mounted to the top of the fiberglass shell and are about 5 ft apart. While this was initially kind of distracting, after a while, you mentally nulled out this clicking sound. We need to experiment on the next dive operating the OTS gear on another channel and see if we get the same results.
All in all, it was a fun and productive series of dives. I am hoping to do some deeper dives in about a month. As I have not done unmanned max depth test, I have been keeping the dives to less than 60 ft.
Cliff