Policy is to not take cellphones out on mission. I did some short range nav fam runs near Bahrain and you lose cell phone signal pretty quickly once you get away from land anyway.The real facts about why this happened are still scarce but what is know really does point to a major navigational f$#k-up by the boat crews. This is especially sad because they could downloaded a marine plotter app on their cellphones for free that would have kept them out of trouble.
I did a tour in Coastal Warfare (now NECC) and (at the time, at least) the training and preparation provided by the TYCOM for riverine squadrons was inadequate at best. Of course it was a RC community at the time and is now active duty and I don't know what has changed.
NCW became MSRON, who does grey hull port/harbor security stuff.
They merged with RIVRON, who did the green boat stuff that Marine SCCO's and 'Nam era small boat guys used to do + the RCB open water mission to now become the composite CRF squadrons.
These boats are fairly new CB90's (RCB's) supposedly equipped with late-model Furuno plotters. Don't know whether the plotters (on both boats) were inoperative, there was no one looking at them, or there was something else going on. There are reports that one of the boats was having engine trouble but also reports that wasn't the reason they ended up in Iranian waters. If you are a US Navy crew in a disabled small boat in the Persian Gulf, your number one mission is to avoid ending up in Iran... not sure how they hosed up so badly. I all but positive the Iranians didn't "jam their comms" or whatever to cause this incident.
In addition to the Furuno (which isn't that great for nav SA anyway), they should have had a separate nav display that took the mil-GPS receiver inputs and plotted it on an electronic chart display. Very similar to what ships have in basic functionality. I doubt they were both inop, they were very reliable. Unless they were spoofed, but that should be evident to investigators in tracing the track logs. Best guess is they lost SA due to concern over fuel state and engineering casualty combined.
Concern over comms with the refueling ship may have been an issue. SATCOM had a tendency to drop off for 15 minutes or so for no apparent fucking reason every few missions. Having redundant comms channels would have been nice if that was the case. Murphy may have just hit extra hard that day.
CDR Salamander and others around the internet have made the likely-accurate point that there was a major failure of leadership by the chain of command that these crews set out to transit from Kuwait to Bahrain and ended up in Iran. There is likely a long list of failures (links in the chain...) that led to this incident. Probably there should be an investigation into the training, preparation, and procedures for operating RCBs in the Persian Gulf and probably several CO's in the chain deserve to be relieved. I suspect, for political reasons, that wont happen. I also suspect that the Coastal Riverine Force has concentrated more on MESF (Maritime Expeditionary Security Force)-style training (ashore security stuff) vs small boat handling and navigation since they were only recently created by the merger with MESF, and that was a contributing factor to this incident.
The training focus is almost certainly the root cause. I think it has more to do with the number of craft and missions that has been crammed into the composite CRS construct while training resources have been diminishing than anything else.
When we were RIVRON, we had our hands full with a 6 month workup period to convert our Det to RCB's + 6 month deployment. And that was after we went to a single type of craft, which is far more capable, but also more complex and maintenance intensive than anything else in the CRS inventory, whether it's a MSRON or RIVRON sourced craft. The current force structure has them with a mix of all types of craft in the force, with more coming online.
Combine that with pulling training funding from RIVRON side assets to level load with MSRON's shortfalls, and you could have problems.