they don't receive another one what can they do with the four signals as far as triangulating these? >> this is pretty good, even if they didn't hear another ping, they are still in pretty good shape to start deploying the autonomous vehicle. the reason they hesitate on deploying it is that it covers -- any particular space, any particular part of the ocean much slower. it is about seven times slower than the ping receiving device. so you want to use that as much as you can as long as the pingers are still in play. get as clear a picture as you can. and then you put in the device with the side scan sonar. they have enough information to do that right now. they just want to get it as precise as they can. just to speed things up ultimately. >> and one thing angus houston mentioned is that it takes time once they put this vessel under water for them to be able to