Auxiliary surveillance system giving problems(trawler fans)
It´s partly similar to all inlinefuses installed to protect instruments. So far onboard Dora Mac,inlinefuses have only created problems being very hard to find, and in this case there´s an extra surveillance system that causes coolant leak out at sea.
For every new auxiliary system installed you add a risk of future leaks from connections,hoses or o-rings,and so the benefits have to outweigh potential backsides.
To me this is a problem with most modern boats. They have become far more complicated than only decades ago, and allthough all fancy systems add comfort they do keep their owners busy.
On the pictures the crack is revealed cutting temporary repair open and so replaced with new a hose.