You really shouldn't solder most connections on a boat. The problem with soldering a connection, is the solder causes the wire to become more rigid, and the connection is more subject to fatigue failure. Also, a soldered only connection can fail under a high load—which is why the ABYC specifications say that all electrical connections must be mechanically fastened, even if they are soldered.
I'm really not seeing how a soldered connection is a downfall (even on a boat). All crimper connections just squeeze a soft metal connector onto the bare wire. Normally, you can pull it off w/ bare hands. I'm not talking about a firm tug, but if you yank on that thing, the connector will come off before a soldered connection will break. And as far as vibration making the wire brittle, I've yet to see a connection where it broke due to the soldering. HOWEVER, I've seen litterally dozens of crimped connections fail under much more favorable conditions.
The ABYC reads as follows:
Battery lugs designed for soldering are the only place
where the standards allow solder to be used as the only
means to secure a terminal connection to a conductor (E-
22.214.171.124). When stranded conductors are soldered they
become, in effect, a solid conductor. This solid conductor is
then susceptible to cracking and breaking from vibration
and flexing, resulting in high resistance and heat build-up.
For this reason, solid conductors of any kind are not
allowed by ABYC. In the case of a battery lug, it can be
soldered if the solder contact length is at least 1 ˝ times the
diameter of the conductor.
Maybe they have 100's of documented cases showing solding is a poor way to make a connection. Which is strange, b/c its stronger and provides less of a voltage drop over the connection compared to crimped connectors. Not to mention its easier to get a waterproof connection over a soldered joint compared to a crimped one. And the brittle part? You shouldn't run your wires where they are going to be flexed a lot in the first place, but I'm willing to bet those butt connectors don't flex a whole lot either. And testing a crimped butt connection compared to a soldered join in a linear pull test, the solder will win.
SD, I don't want to sound like a ***** and this argument wasn't directed at you. I'd like to thank you for that reference, however, from my experience people don't like to solder connections because it is too time consuming, and a lot of the time they don't do it right. Not enough flux, too much solder, overheat the wire, in which case I agree that the crimped connection is simple, easy, and usually does the job. But to say that soldering is bad on boats just seems like a blanket statement that isn't correct.