It doesn't matter whether it's Catalina or Universal, the hose is there, so use it!
I've been using synthetic motor oil for the past five years. It's more expensive, but doesn't leave the goop that regular oil does, at least that's what's been reported. I also use Fram filters instead of the more expensive Universal filters. You could probably get Kubota filters less costly from the tractor manufacturer - do a Google search on Kubota and find a dealer near you. We found one in Livermore, 30 miles from here, and a $42 thermostat costs less than $20 from Kubota.
I built a connector from the oil drain hose to the hand pump I use for oil changes. See the picture.
Instead of Ron's electric pump (see below), I use a simple Par Jabsco hand pump.
From my colleague, Ron Hill who is a "master" C34 skipper and maintenance guru (this is from 1999 and he's still going strong):
Oil change. My C34 is going into its 12th season with almost 3000
hrs on the engine. I have NEVER used nor would I recommend using Herb's
method to change/drain the oil. The M25 engines, according to
Universal, have a crush washer in the bottom of the drain plug. As you
probably know, a crush washer is meant for a one time use. With the
attachment provided by Universal to suck out the oil, it's much less
messy and less apt to ever have the plug back itself out or cause a
leak. The crush washer and plug are similar to the oil drain plug on a
VW Beetle engine -- if you've ever owned one.
I've been meaning to write up a Mainsheet article on how I change oil.
First of all, I use an engine dip stick heater to warm up the oil,
rather than running the engine and circulating all the dirty oil back up
into the upper portions of the engine. I then use the ParJabsco (Porta
Quick 12volt Oil Changer) pump oil changer to suck the oil out. It will
also suck out transmission fluid as I do not recommend draining the
transmission fluid by removing the drain plug (steel threaded drain plug
going into threaded aluminum housing -- I think you can see the
potential problem). I bought my changer back when it was $75. I see
they are now $150. What is really nice is that you can put a 1 gallon
disposable jug inside the changer and have all of that black nasty oil
go into a jug, cap it, and take it to the recycle center without
dirtying up the oil changer. It's amazing, but this oil changer sucks
out 4 quarts of dirty oil I use chair tips to cap the ends of the
hoses so they don't leak. As far as removal of the oil filter, I
unscrew the oil filter until it is just loose. Then I drill a hole on
the out board topside of the filter and I mark the port side of the
filter with a marker. Then I take a medium size empty coffee can, hold
it under the filter, unscrew the filter so the mark is at the bottom and
then drill another hole in the top side of the filter. This allows all
the oil in the filter to drain into the coffee can. I previously had
stuffed a number of paper towels underneath the area where the filter
joins the engine. When the oil stops dripping from the filter, I
unscrew the filter, let it fall into the coffee can, clean up with the
paper towels, put the dirty paper towels in the coffee can, put the cap
on and dispose. There are no dirty gloves involved and no mess.