Avionic and marine frequencies on a handheld

I want to be able to communciate over the marine channels as well as
avionic frequencies using a handheld.  Does anyone know if this can be
done?  I am pretty sure that there is no off the shelf handheld that
will do this but I was wondering if a standard avionic radio can be
modified.  Marine frequencies are between 156-163MHz, FM.

Thanks in advance.

Ian