Chuck wrote:
"Or that only vertically polarized signals can be intercepted by ships
at sea?"

I served on a navy ship in WW-2. Our antenna was a low-L. It could
intercept either polarity but responded only to line of sight and
high-angle signals. This was a deliberate design. The Navy did not want
our emissions QRM-ing the world. Our range was limited to about 500
miles. We could contact our shore destinations at about 2 days travel
from them (our ship was slow).

Best regards, Richard Harrison, KB5WZI