If you survive a ditching you will not survive for long in the ocean without rescue. Surely location is a vital ingredient?
All transport aircraft are required to carry Emergency Locator Transmitters that can be manually deployed by the crew after a ditching. Therefore your point about the delayed rescue after a successful ditching are invalid. However, I'm not sure about the regulations regarding automatically deployed beacons that would be useful in the case of a crash rather than a ditching.
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