What does oily bilge water near the shaft seal mean on my cruiser?

[Kenneth_A]

I was checking the bilge on my 28-foot cruiser and found a small puddle of what looks like oily water near the shaft seal. It’s not a steady drip, just this greasy residue after a weekend out. I’m trying to figure out if this is just normal weep from the packing gland or if it’s a sign the stern tube needs attention.

[GraceR]

I've seen that patch after a weekend in the marina. it’s usually a tiny weep from the packing gland and not a big deal if the bilge stays mostly dry. I tightened the gland a hair and watched it for a few days; the patch faded and didn’t come back.

[MarkYM]

If it’s real oil instead of just oily water, it could point to the stern tube bearing or a splash of gear oil from the drive line. Look at color and smell and compare with engine oil if you can. If it still shows up after running, that’s a clue it isn’t just water.

[NoraGH]

Hard to tell from a single weekend patch. I’ve worried about it and then found nothing obvious, and sometimes it just seemed to disappear with a heat wave or a rain rinse.

[Stephen.H]

Did you notice if it shows up more after you run the engine or after the boat sits for a while?