Changing the oil in the diesel auxiliaries is usually a messy process. For those boaters who use their boat a lot, and particularly those who travel the ICW, the oil will require changing many times in a year. If your boat is equipped with Westerbeke 42B diesel (and perhaps other models), you can speed-up the process and make is a lot cleaner at the same time.
After trying various hand-pumped vacuum containers with so-so success, I installed a "Qwik-Drain" electric pump (less than $100 at that time), mounted to the starboard side of the engine compartment (refer to the picture). The 42B has a hose plumbed into the crankcase so the pump was connected to this hose. The thread on the engine hose was not the same as the thread on the Qwik-Drain hose, but I found a double-threaded fitting in an auto parts store, that matched the two ~hreads. Now all I have to do is put the discharge hose of the pump into an empty one-gallon container (saved from the previous oil change) and push the button on top of the pump. VIOLA - within about two minutes, the crankcase is empty. I plug the discharge hose and tuck it behind an adjacent bracket holding an automatic Halon extinguisher (the red thing right above the pump), which keeps it out of the way.
Of course, the filter must also be changed, so I use a technique suggested by Larry Berlin, of the Engine City Tech Institute (Mack Boring & Parts Co.). This uses a one-liter plastic beverage bottle, cut to look like a scoop, with the cap tightly secured (refer to second picture). This is placed under the oil filter so that it is tight against the filter/oil pump interface. As the filter is unscrewed, the oil runs into the scoop. As the filter disengages from the engine, it is tilted so that most of the oil in the filter runs into the scoop. This process captures most, if not all of the oil in the filter. The scoop is then emptied into the container with the rest of the old oil. Some engines might have more space around the filter, which would allow using a two-liter bottle. In this case, the filter can be slid into the scoop and handled that way. The 42B does not have that kind of access.
Having made two round trips on the ICW, for over 4000 miles each, hence requiring changing the oil about 10 times per trip, this oil change process has saved much frustration and mess.