Thanks, Lepke, for sharing your experience. After measuring and shopping
around I came to the conclusion of keeping our old plastic gland - the greasable ones (and everything else for that matter) I could find were all too long for our shaft space. The one we have now is about 2cm long after the hose, and there's only about 2 more cm until the shaft coupling. The tool we use for tightening is made of a rolled steel
plate so that it can grip the narrow bolt head
It does work fine so far, it's just a bit annoying having to tighten it while docking
to prevent water from coming in plus I was concerned about its reliability
. As you mentioned, the material might be of importance since everything will be submerged in sea water inside the hose. Plastic might be good since the moving parts
will not corrode together, but might melt if the water flow is too low.
So, I'll just exchange the old hose and the stuffing material and make sure that we don't forget to adjust the water flow to a drop per minute when heading off. And maybe I can find a plastic container to fit under it to collect the water.