The 'landing' in the Hudson was a ditching with significant g as the engines went into the water.
The reasons for the ELT's failing - broken antenna, going underwater etc are well known. So now get a couple of engineering undergraduates to design them so that they work! It is not difficult but it appears that the manufacturers are perfectly content to deliver equipment that demonstrably fails EVERY time it is needed.
Note that if the ELTs worked on MH370, it would have been found within 7 hours of going missing. How much has been spent searching for that aircraft again? Probably enough to design,manufacture, purchase and fit a nice shiny new functionalELT for every widebody flying.
Instead off go the avionics engineers fresh from their total failure to create a functional ELT, trying to sell ever more sophisticated tracking devices that will also fail, but bring in far more income.
A question that operators should ask the avionics industry is: "If you cannot create a working ELT an extremely simple device, why should we trust you to create a sophisticated tracking device?"