Bertram's hydraulic steering hoses run risk of burst failure so now replacing them all. Some brands put expiration date on them with 15 yrs. about the maximum rated life.
Yep, Thru the years we have had a couple of hose failures on our Bertram. They used that hose everywhere for air, fuel and Hynautic steering. The outer rubber sheath takes a small crack, the inner steel braid/mesh rust aweigh quickly. Lean on that rudder and the hose fish-lips/blows. All fuel and Hynautic hoses have been replaced on our Bert. Soon, I will resolve what we are going to do with our fly-bridge, then my original air hose (wiper motors and horns) issues will come to past.
They appear to be rubber over some type of mesh. Previous Bert had copper (or similar color metal) from helm about half way to rudders but this all rubber and mechanic said the metal went bad so they changed to all rubber. When I changed the rubber on previous boat the hydraulic shop pointed out mine had years ago expired.