I just replaced mine a month ago on my 1989 catalina30. We needed 23 ' of hose , which shocked me but that's what it took. I had help from a friend who had done his , and his went smooth! Mine ,not so much. We made a sleeve to join the old to new so we could pull it through as he had done for his, but couldn't budge the hose. After much thought as to what may be happening , we removed the stove and cut a inspection port in the liner and from there could see that the hose was being wedged down between the liner and hull. At this point with the two of us and my son we would lift , push and pull and within an hour had it through .i should add I replaced mine as it was picked up on my survey that it had cracking on the hose near transom.all is working great now .
Cheers
Laine