Dirty oil / waste oil


I am a shipbuilder and wondering if i can get some help from a ship engineer about a few things. Basically, Im just trying to understand the system better. I have no problem asking dumb questions on here but dont like to do it in the yard.

So, excuse me if this is a dumb question. Im building a tug, the bilge system and the fuel oil manifold dump waste oil in the waste oil tank. It then goes through a strainer and pump, a bunch of valves and guages to a discharge on the deck. Also connected to the system is a suction hose and the dirty oil tank. But, other than being connected to the the waste oil system, i dont see why you would use this tank. Nothing is directly piped here. Are you supposed to run the waste oil through the strainer twice? and after the first time through, its directed to the dirty oil tank, then shut the valves off and run it through the strainer again and then to the pump out station? Or is it a hand filled tank? I can obviously wait until its underway, but I’d prefer to have a better understanding of its use.

Thanks a lot.

One of the tugs in the fleet we have converted the sewage tank into a oily waste tank which is usually filled with bilge waste which is mostly water and a bit of oil. The boat also has two dirty oil tanks. We do oil changes into the dirty oil tanks but keep the bilge water in the oily waste tank. The reason, we get paid for waste oil but we have to pay to dispose of oily water.

Without seeing the installation it’s kind of hard to picture it.
Cutting a little water off the fuel tank bottoms is a normal thing.
You should be able to add to the dirty oil tank by hand.
Oil changes should never be dumped into the bilges.
Filters should never be dumped into the bilges.
If it’s powered by 2-cycle engines, the air box drains should be dumped into the dirty oil tank.
All the waste oil generated should be added to the dirty oil tank.
The bilges should be kept as oil free as possible.

The filter/strainer before the pump is probably meant to protect the pump.

[QUOTE=Helpmeplease;78667]I am a shipbuilder…[/QUOTE]


Something doesn’t smell right … “shipbuilders” don’t need to ask internet forums what tanks and pumps are used for.

I think shipbuilders just build to specs., they don’t have to understand or agree with the architects plans.

At least that was my experience with the only new build I ever dealt with.
I had to battle my company for change orders, not the shipyard.
And since the architects plans had already been ABS/USCG approved, changes were real battles.

I agree with Steamer.

Also, why is the bilge system connected to the waste oil system, except at the oil outlet of the OWS? Ahem.

Somethiing doesnt smell right? Really? I dont sail. I work in a shipyard. Have for 15 years. pipe fitter, ship fitter, welder. I was missing some information and got confused. All set now. Dont worry about it. Thanks for the other help though.

Hmmmm, on reading this again I wonder if I just mis-interpreted his “shipbuilder” title. If he is a guy who works in a shipyard where they build tugs he might not know how or why the system works or how things might be connected. The reference to the fuel manifold being connected to the waste oil is also a flag.

Giving the guy the benefit of the doubt, Seadog covered most of it.

The hose is probably fitted so that sumps can be pumped to dirty oil or directly ashore. Are there quick disconnects on the hose and the engine sumps? The strainer is definitely to protect the pump because all kinds of crap goes into the waste oil/save-all/sludge/slop tank. Yes, the WO/SA/S/S tank is normally fitted with a sounding tube or other opening in an easily accessed location so that small containers of waste oil can be manually dumped into the tank.

There shouldn’t be a connection between the dirty/waste oil and or bilge lines and the fuel manifold. If there is a centrifuge it should have a discharge to the waste or sludge tank and that is where any water would go.

If you can get a drawing you will be able to see how the tanks and piping are related and what cross connects are possible. Generally, the systems are designed so that the possibility of cross contamination is minimized … not impossible but as sailor proof as can be and still be worth installing.

There will be a drawing someplace on the boat or in the office that you can use to trace the lines. Good luck and have fun.

“Pointy Sticks” partially revoked on Fridays ! Good.

Indeed, take a digital photo of the schematic (or draw one yourself) and post it here. (Leave the yard / boat name details off).

Many here can explain how the system will / would work. Or not.

Note some yards do not actually install what the schematics show, and this can be kinda problematic until it gets detected and sorted out.

Dirty or ‘Used’ oil and Waste oil are two entirely different animals from an EPA,DEQ,ETC.ETC point of view. Used oil is a commodity, Waste oil is a liability…

Thanks for the help. Something doesnt smell right tho? Really? That’ll teach to me to try to learn about the system im putting together i guess. Anywway, yeah, I work for a shipyard. I was confused about the drawings, but i was missing some crucial information, which was why. Plus the sketch I was given was garbage. All set now though.

When you build ships, you can consider yourself a shipbuilder, right? Ive been building ships for 16 years. And I know what Im doing. I also have a pretty good understanding of how they work, but Ive never actually operated one. Except sea trials. Thats not my job though. Sometimes , its tough to get answers to questions around here, so i took to the internet. Didnt think it was really a big deal.