I used a Ritchie unit for about 15 years with my previous boat, and it was
the first thing I looked for on ebay when the PO of my present boat insisted
on keeping his.

Yup. I had three, sold one of the others straight off. The one I have is in
good shape. I know a few people who swear by them and a friend of mine made his
own, larger unit that works even better than the Ritchie.

RB