Smelling out a cassette problem

Warning: this post contains disgusting content!

It began a few days ago. The smell of stale wee grew stronger all the time, despite my thorough cleaning of the pan. We had arrived at Welford and taken the offside mooring at the very end, so were conveniently placed for the services. I pulled out the - not very full - cassette and immediately found the source of the smell ... and managed to spill some of it on the floor - yuk!

A puddle of the yellow stuff had formed on top of the cassette. Oh dear. Why?

I took it to the service block, emptied and rinsed it. Then I slid off the cover and operated the device to open the black plastic disc which seals the cassette. With a cloth I started cleaning the rubber gasket, and found that there was a lot of what seemed like limescale inside the groove. I think this must be (sorry about this) solid matter precipitating out of urine over the course of years. This hard stuff was probably preventing the rubber gasket from sealing properly.

With as much of the scale removed as I could, and after another rinse, I installed the cassette back in place. Prior to this I cleaned the cassette housing as best as I could. Then I cleaned the gasket in the other cassette.

After several hours it all seems to be working as it should, i.e. no leaks.

So ... if you have cassettes, you might like to clean the gasket before you get the same horrible problem.