Do you need a new one or is it just the little magnet that's disappeared from one of the paddle ends? If it's just the magnet that's disappeared you can just replace it with a small bar magnet imbedded in epoxy. I had this problem and fixed it this way. I have one or two of the little magnets and can post you one if you need it.
AW Marine quoted me over £30 for a new plastic paddle wheel! Don't know if the new guys will be more realistic.
[/ QUOTE ]Before you buy a new one, check that the little axles aren't bent or wrongly fitted. There's a little stainless steel axle screwed into each side of the housing; they should screw in just enough to hold the paddlewheel away from the sides of the recess, but there should normally be a little bit of sideways float on the paddlewheel. Clean and antifoul the paddlewheel and the recess, and it should be fine.