Re: Why a water separator?
Most water problems are more likely a result of actual water entering your fuel tank or getting into the fuel tanks at the dock. Condensation: Not so much. Ethanol? Well.... maybe, maybe not.
See... Marinas are, generally, surrounded by water. Boats tend to be around a lot of water, too. Boats have been known to float on water, splash through water and even have some water splash onto hatches, caps, vent openings and just generally all over the darn boat.
I refueled in the rain one time. The marina didn't have a covered fuel dock. I don't think I've ever seen a marina fuel dock that wasn't very close to the water or one that was covered from the elements.
Most of the marinas and fuel docks I've been too (actually, ALL of them) have pumps that pre-date electronics! Most of the gear is old, it's weathered, and the hoses are in worse condition that Abe Vigoda's skin. Yeah, they're all alive, including Abe, but you'd swear they were dead.
Now... considering all this, please ask yourself: Should boaters use a water-separating fuel filter?
Now, there is a 'dry bilge' club around these parts (iboats) somewhere, and they are sometimes part of the "OMG, three drops of water came over the sides" club, and they run the boat back into the garage and modify their Wet Vacs to suck up all known nanoparticles of anything that came close to water. They tend to skip boating days because they don't want the boat to get wet (laugh, because they've been here and admitted it*), and they trailer their boats to the nearest/cleanest Shell station for fuel on a clear, sunny day... once, maybe twice per year. MAYBE, just maybe, they can opt to skip the water-separating fuel filter.
*YES... There have been several posters who skipped beautiful boating days because the boat looked so good on the trailer or in the garage, so they didn't go boating. They even CREATED the threads on the subject!
