Well, Joe, that certainly establishes you as our resident filter expert. I
believe you 100%. Now that it's clear that we are having an informed and
intelligent discussion, let me get more precise and specific to my
situation.

"Joe" wrote A vortex is made in the bowl that
helps seperate the water from the
fuel.

This is clear from the design of the filter housing. The key word in your
statement is "helps". The issue is how much the help is. If it is 80% -
90%, you could say that the separator is essentially worthless at low flow
rates. If it is something like 10% it is not going to be critical in most
applications were simple gravity driven separation will do a lot of the
work.

Running crew boats with their notoriously wet fuel (that I've heard about
from others), wringing maximum performance out of the filters could be a
significant operational consideration. At best, you might still be wishing
the filters were doing a better job. That last 10% of performance might be
quite noticable.

I saw no hint of water or other contamination for two seasons. Considering
how little attention most boaters up here pay to the subject (just saying,
"do whatever it need" to the yard once a year), and how few I see being
towed in, it's probably typical for this climate and fuel infrastructure.

When I look at the smallest filter housing, I see that it is rated for 15
GPH. Scaling it down to preserve the same flow dynamics at the less than 1
GPH I'm usually drawing would make it so small that the filter wouldn't last
long. It would have to be a completely different design, a swirl separator,
a separate chamber for water to collect, and a larger filter housing.

I'm not likely to get "swirl boost" out of stock Racors anyway at flow rates
less than 1/15 th of maximum. The simple gravity separation will be more
effective in a larger volume and slower flow, that's why some vessels use
day and even separator tanks. A larger filter will last longer. That's why
I don't see a downside to larger filters in my fairly common situation.

For a crewboat, or a yacht picking up lots of third world fuel in a similar
climate, no doubt in my mind that you are spot on about the proper sizing.

The jury is out for me on additives. A yard manager with a lot of
credibility told me not to put anything in my fuel so I didn't for two
years. Then, I had just a few hiccups in an otherwise smooth running engine
with a nearly empty tank and began to find alge in the filter bowl. I put
in the StarTon and the bowl filled up with green stuff and the filter turned
green black although the engine ran fine. One tank of fuel after the filter
change, the bowl is clear. It certainly looks as if stuff was flushed out
of the tank that would otherwise be building up. Keeping it moving through
to the filter in smaller amounts instead of building up so that a big glob
gets sucked up in rough seas, which is when it invariably happens, seems
like a good idea.

--
Roger Long