Sticky sink - pump out?

[concentrik]

The twin sinks in the galley connect via a 'Y' tube to the 50mm hose, which then goes straight down and emerges through the hull. The waterline is just a little below the 'Y'.

The slightest gunge from dishwashing seems to form a 'plug' in the lower hose and when the sink plug is removed the dishwater flows not to the sea but back up to equalise the level in the other sink! Judicious replacement of the plug and plunging releases the blockage and everything drains nicely.

The tubing is not blocked anywhere.

I'm wondering about fitting some sort of 12v macerator type pump which will operate automatically wwhen the dishwater hits it and evacuate the sink toute suite... but I can't find one. Any pointers or other suggestions?

 

[Tranona]

Are you sure it is a 50mm hose? awful big for a sink drain and difficult to see how you could block it. Sink drains are more usually 19mm or perhaps 25. Apart from reducing the number of outlets in the hull, can't see the benfits of draining 2 sinks into one pipe - so fit another seacock so they drain independently.