Mystery oil slick found

About two weeks ago I noticed a small sheen of oil after my bilge pump ran. I figured one of my tanks had been over filled last time I purchased diesel in St. Martin. So I alternated tanks to burn off about 5 gallons from each. You see my tanks have several opening on the top for the sending unit, the sounding rods, and the inspection lids and the seals will leak a bit if the tank is over filled. Yesterday I noticed an oil slick after the pump ran. So this time I opened the cabinets with access to the diesel tanks to inspect them, no leeks. So next I pull on the nitrol gloves, head lamp and paper towels to inspect all the fuel lines and connections. Sometimes a hose clamp is not as tight as you thought it was. All the fuel lines are oil free. So I inspect the stern drop into the bilge sump. Ugh there is a shine. There is a diesel diaper at that point int he bilge just incase a fitting drips. I get a fresh diaper and pull the old one up. It is soaked with oil, not diesel, but oil, clean fresh oil. I put down a new diaper and then go the the aft lockers where I store about 5 gallons of 15W40 oil. Sure enough one of those has cracked and leaked it's contents into the bilge. Lucky it is the one I used to change oil a few weeks ago, but all the same about 2 quarts of clean oil dripped down the hull to the diaper and into the bilge. I cleaned the locker and then added an emulsifier to the bilge to turn the oil into soap. Problem solved, but now I have to watch the remaining 4 gallon jugs to make sure they don't spring a leak.
Went to Mac's Pizza restaurant last night. It has new ownership, but the pizza is just as awesome as it was 20, 15, 10, 9 years ago. (see I've been here a few times).