It's crazy that they only made it 20 miles from California before hitting weather serious enough to sink the ship. I'm surprised they wouldn't have literally seen it coming before departing.
Believing [1], the wreck has already been found in 2009 and identified to be the USS Conestoga in October 2015. Only the official announcement was made now.
It's not unheard of for ships to be overwhelmed by heavy seas. Here's an accident investigation report into the loss of a large freezer trawler in storm in the Barents Sea. The ship was thought to have lost steering, went beam on to the seas and was overwhelmed due to an incorrectly secured hatch. https://www.gov.uk/maib-reports/sinking-of-stern-trawler-gau...
Well radio was certainly available at the time this ship went down, however if the article suggestions are correct then waves may have crashed through the wheelhouse and that likely would have flooded out the radio room as well if not just the general mayhem of the rough seas. they could have simply engulfed, as in to go bow into a big wave and never come back out.
I cannot find information the directly states what type of radio it may have had
The officer of the watch would be expected to plot the position on the chart every 15-20 mins so even a DR position would probably have been accurate to within ~10 miles.
"95 years after disappearance, the US Congress is found"
You know those nights ...