Not related to safety or sailing, but still a priority for Red Ranger. Also, it's something we'd like to do while we've got a few weeks with West Marine and Radio Shack less than ½ mile away.
We have a doddering old marine cassette player. Cassette. It has an auxiliary input wire that we can plug into a computer or an iPhone to play music. But there's also a battery issue. The audio system (such as it is) draws little power. Leaving a computer running, however, brutalizes the batteries. Yes, we can use an iPhone, which is somewhat more thrifty, but our waterproof cases make this a bit awkward.
Last night, for example, the house bank slipped to 12.0 V. Too many rainy, cloudy days in a row. At 12.0V the inverter starts turning on it's warning lights. The little 12V-to-USB device we use at the nav station stopped working. We haven't run the engine in two weeks. I don't want to break out the generator in the marina. And shore power isn't built into the slip fees; we have to pay for each kilowatt-hour used.
Liquid Therapy uses a Bluetooth interface for their entertainment system. That's very, very nice. Further, most modern music systems can read from a USB drive, so we can "burn" a "mix-tape" of songs, and plug that into the stereo without having to leave anything else running but the music.
A CD was about 600Mb. A 4Gb USB drive, then, is over 6 CD's worth of music. Most of the day without a repeat.

We think we've found what we want. And we think we found a place to put it that frees up some storage.
DIN vs. non-DIN
There are, of course, a kajillion and a half products. We don't — strictly speaking — need a marine system, since the stereo will be safely below decks. But. It seems prudent to focus on marine instead of automotive.
West Marine, Defender and Amazon have lists of stuff. Lists. How to filter?
I used amazon.com to filter. Not for a particularly good reason, but they had a tidy list; less than a dozen products, not a kajillion and a half.
It turns out that mounting becomes one of the serious decision factors. Not all marine stereos have a sensible gimbal mounting bracket available. Too many are DIN format units that have a sleeve that mounts into automotive-style trim. Way too many. Far, far too many.
For example, I really liked the Clarion M502 which is described as "Mechanism-Free" — no moving parts — no CD, no DVD, no cassette. However. I couldn't figure out how to mount it; Clarion doesn't seem to make a handy gimbal for it; I worry about buying a Jensen "universal" gimbal mount for DIN-style stereos. How do I know everything will fit together? What if the Clarion or Jensen aren't totally standard?
The Polyplanar MRD85i fits the bill with respect to Bluetooth and a gimbal mount.
But wait, there's more...

The Fusion MS-IP700i on the Amazon result set is over-the-top. Fusion, however, makes a million marine stereos. This further line of research lead us to what looks like a solution to the entertainment problem.
Enter the Fusion MS-RA205. This is not a DIN automotive-style unit; it has a more sensible panel mount. It has an add-on for Bluetooth (the MS-BT200).
It has a bunch of other features that aren't relevant. The form factor makes this a total winner.
New Holes
The faceplate is somewhat smaller than DIN automotive faceplate, so we have some additional flexibility in our installation. All we need to do is find a space the right size for the face place.
While cutting yet more holes in the teak is not the best idea, there's a void behind the chart table that's available. The current location for the stereo is bothersome because (a) it blocks off a few cubic inches of space we'd like to use; (b) it's behind a door that we have to open to turn it on; and (c) we have a silly wire that randomly hangs out of a cabinet.
A little quality time with the Fein multi-master should create the minimal hole. Four screws and we can mount the stereo in a better spot. It's only a few inches from the current location, so the wires just might reach without a lot of painful rework.