After sitting in Freeport for nearly a week, the part for our watermaker finally showed up. The picture below shows the hose and fitting that was leaking. Water was flowing pretty steadily from the joint where the hose enters the fitting.
These are special high pressure hoses and fittings to handle the 100 PSI of feed water pressure. Normal water hoses can't handle that, and these Parker nylon tubes and fittings are much easier to work with than copper. They have a clever retainer and o-ring seal that makes a tight joint by just hand tightening the nut. But when something goes wrong you are shit out of luck without the proper replacement, and the local hardware store doesn't carry them. I now have a note to myself to get an assortment of these as spares for the new boat.
My original suspicion was that the o-ring had split or cracked, but it looked fine. I tried turning it around and that made no difference either. And I couldn't see any split or crack in the fitting or nut either.
That hose was not secured until it reaches the pump at it's other end, and when the water maker shifts direction (it's like a piston that goes back and forth), the hose flops around a bit. My best guess is that the flopping motion eventually caused a crack in the fitting. But even after the new fitting arrived and I completely removed the old one, I couldn't see any sign of a crack - at least nothing definitive. There were a few lines, but I couldn't say they were cracks and not just molding marks or scores in the surface. I even stuck a couple of screw drivers in the fitting ends and flexed it to see if any of the lines opened up, but I couldn't see anything. The new fitting works and doesn't leak, but I hate repairs where there is no clear smoking gun causing the problem. But I now have that tube secured so it's not flopping around any more.