Most ocean going ships will have SoNaR, but not all.
I questioned this once on a large passenger vessel and was told that since they used recognised shipping channels with known depths that it wasn't quite as important as some people assumed.
I don't doubt that most/all new builds are fitted as standard, but this is only quite recent on passenger ships.
Having SoNaR would be nice though for anything from fishing boats to cable layers etc
Stuart
