Gosh, thank you so much, Olivier. That information is quite helpful.
Sadly, we had already done the installation in the water by the time our internet connection returned and we were able to read this. And, you're exactly correct: it's very difficult to clean the fiberglass tube of the old silicone caulk sufficiently before inserting the new hose and new goo.
Now we're pondering whether or not the job has been done sufficiently. Thinking about whether maybe we should re-do it ourselves now after plugging the hole somehow from the outside and heeling the boat over a little onto it's starboard side, or perhaps leave it as-is now, but put it on the schedule for re-do with next haul out. We're waiting for sealant to fully set before we decide.
On another, more pleasant note...the exhaust hose Amel used must have been some pretty fantastic hose. After 23 years, it was still intact and functional. Although it was definitely showing its age and needing to be changed, 23 years is pretty impressive service for a flexible object exposed to a hard life.
Thanks again, to all.
S/V Aloha, SM72