A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Tony Oz
Date: 2017 Mar 31, 11:58 -0700
Sure I'll try to stay as on-topic as possible.
I'll try to not go overboard with being a technophobe or luddite either. So, yes my interests are limited here with strictly the topic of the Emergency Navigation. As you have already set the boundaries - I'll try to discuss only the radio reception for the timekeeping and for the direction-finding (but this particular field is rather new to me).
To make a decent grounding for a crystal radio you'll need a metal sheet of approx. half-meter by half-meter size properly soldered to the GROUND wire of your receiver, this metal plate should be put into the water. As all ancient manuals for radio listeners used to warn about the lightning strike hasard - I'd too suggest to remove the grounging plate off the water when the receiver is not in use AND in vicinity of thundery-looking clouds.
What type of cables do support the mast on yoour boat? Are they ropes or metal cables? If they are metal - I'd try to use them for an antenna.
RDF is much trickier - apart from a directional antenna in your rig - you'll have to account for radio-wave propagation direction change when the wave passes from the ground to the sea - just like the refraction correction for the light beam - we'll have to correct the apparent azimuth for the (unknown) ratio of the distance covered by the wave over the solid ground to the distance covered (with slightly different speed) over the water. It's tricky indeed - if we are to expect reasonable accuracy of our radio-LoP.