Do you check the levels in your hydraulic steering regularly? If so, has it ever gone down lower than you can see in the top of the steering wheel control unit?
What you have 'may' be air in the system, hence the turning wheel, but then again, it could also be the steering wheel unit needing some attention. If you're not sure, it would be wise to get advice from a local who can look at it and tell you for sure, since if this goes wrong when you're out, it could be a nightmare.
I am just about to replace the hydraulic pipes on my boat now after 3 years - the UV light has got to the exposed parts where they bend, and the outer plastic has now cracked. Although I am certain the inner core is fine, as is the sheathing around that, it's just not worth the risk to leave it.