I am checking with Vetus Marine on parts availability for the 36 year old Vetus hydraulic steering system on the Rasmus. If parts are impossible to find, I will replace the system. Some have gone with new Edson steering, but at a much greater cost then a new Vetus hydraulic system. So, I will probably replace with new Vetus hydraulic system if I have to go that route. To determine the correct size Vetus system, you have to calculate the maximum torque applied to the specific rudder of the boat, in this case a Hallberg Rassy Rasmus 35. I have carefully measured the rudder perimeter and drawn it in a turbo Cad program, which can give the area of the rudder. The Rasmus rudder has a unique shape that cannot be calculated by the basic length x width equation. The cad program does it for me. Below is the rasmus rudder drawing with Microsoft XL calculations following.