Completed a full hose remove and replace on an 1995 IP40(#45) two winters ago. When we purchased the boat in 2002 we noticed that the "system" gave off some pretty pungent odors. We finally traced that down to the hoses. After a good deal of research and a discussion with IP about ties that may not be accessible (there are none) we decided to go for it. We used http://www.sealandtechnology.com/pro...ges.asp?pid=74
306342871 1-1/2 inch ID OdorSafe hose. A 50 ft roll was about $380 shipped. It's 100% PVC. It's a two-person job with a lot of push and pull but it can be done. We ended up pulling the old out trailing a pull line and using the line to pull the new. The old hoses were multi layer with a reinforcing wire to keep their form. You'll need a hack saw or heavy duty wire snips. The PVC is much more pliable when it's heated and we used a heat gun to "soften" it up to get on to valve nipples. We also took the opportunity to add a macerator and rebuild the heads. Good luck.