david, the silt that is supposedly underneath here, will that interrupt the side scanning sonar? >> that was based on something taken a long time ago from a long way away. i don't think silt will be a problem. we always have to worry a bit about sediment kicking up. but in this case with sonar, i don't think it will be a problem. >> and in this case, a plane hitting the bottom would bring up a lot of silt, but that would settle quickly? it would happen certainly not to the level it would impact the sonar search -- >> and the environment, we talked about this a little during the break. and that's oilthr oulnly half t depth. the environment at these kind of depths under the water, it is a whole other world. >> it is a completely different world that nobody has a concept of. 50% of the ocean is above that.