Just to be double sure you may want to purge your system a little more. The way the Hynautic steering works is through its three hoses. #3 is the common return to the reservoir. The pressure to move the rudder comes from hoses #1 or #2, each of which push the fluid in only one direction. So if you had a bubble at the flybridge, the highest part of the system, it is PROBABLY gone. But those little hydraulic pumps, attached to our steering wheels, only move a few cubic inches of fluid per turn. They are made to transmit fluid, not air, at which they are inefficient. So when I have a steering problem I am fanatical about purging the whole system. About three years ago I had just exited a winding channel in the Bahamas when my bridge steering totally ceased. When this happens your rudders will remain locked in whatever position they were. If they were hard over it is impossible to steer using differential engine power alone. I did not like this at all!
So go to the Hynautic manual and your Hatteras Owner's Manual to see how to completely bleed the system. On my boat I have three steering pumps, at the fly bridge and salon wheels, and the autopilot, mounted in my engine room. I have a little green box at the stern near my steering ram. It has a bypass valve that needs to be loosened, letting hydraulic fluid go straight from hoses 1 and 2 into 3, washing all the bubbles back into the reservoir. When open it bypasses the steering ram and expedites the purging of bubbles. I bleed from top to bottom, 100 full turns to the right, same to the left. Probably overkill, but better than underkill. Don't forget the autopilot, if you have one. Just put it into manual steering and let it run from one side then to the other for a minute or two each. Don't forget to gently close the bypass valve when finished purging or the steering ram won't work.
Despite all the talk of the air pressure pushing the fluid up to the bridge, it does not.* Read the manual. It is a closed system and there is pressure on all sides. The main reason for the pressure is to keep dirt or water out of the system. A second benefit is to be an indicator of any system leak by registering the lower air pressure and thereby tipping us off. But if you open the reservoir and release all the pressure and then leave the top open a topped-off system will still work. Pressure doesn't matter.
* Well, perhaps on the initial filling a dose of air might help to push the first drops of oil to the top, but air is not what keeps it up there. Eventually all the air ends up back at the top of the reservoir where it belongs and the system is completely pressurized. Just as milk will remain in a straw when you put your finger over the tip and lift, the hydraulic fluid will remain in hose #3 UNLESS there is some vacuum break (air) in the hose or pump. Even then, the steering will operate unless the leak is in intake hoses 1 or 2 and the pump becomes air bound.
Hope this helps you have a great trip.
Want to enjoy some of this S.E. Louisiana weather we are having.
