Yup. I did try Martin Marine. They usually have what I need but they swore up and down that such an I.D. didn't exist. It does but I had to go to a hose store - New Line Plumbing and Fittings for those in Vancouver, BC area looking for odd hoses.Good to hear after all these years @lnikl . As long as there's no sharp bends in the hose, hopefully you'll have no crimps.
7/8" ID hose does sound like a bit of an odd ball size. Did you try Martin Marine ? They're usually pretty good for odd ball stuff or they'll find it for you.
The hell you say. Arteries get harder with age.
But yeah, the more important things get softer.