[CA] [CA11] acu 200 and type 2 pump

[Chuck - Raymarine - Moderator]

mc360,

Q1. Seastar notes they are each 8.34cu in/ 136.6cc each in volume making it 16.38/273.2Cc total.
A1. In the FAQ addressing how to determine which Evolution autopilot is correct for a powerboat w/hydraulic steering, the subject of how the steering rams have been plumbed within a steering system featuring two rams is addressed. If the steering rams have been plumbed in series, then the total volume of hydraulic fluid to be moved by the hydraulic pump will be equal to the cubic capacity of one of the hydraulic cylinders ... in this case 8.34 cu in, making a Type 1 Hydraulic Pump correct for the application. However, should the hydraulic steering rams be plumbed in parallel, then the total volume of hydraulic fluid to be moved by the hydraulic pump will be equal to the sum of the cubic capacity of the hydraulic cylinders ... in this case 16.78 cu in (2 x 8.34 cu in), making a Type 2 Hydraulic Pump correct for the application. In short, you will need to determine the whether the hydraulic cylinders have been plumbed in series or in parallel. Should you find that the hydraulic cylinders have been plumbed in parallel, then the Type 2 Hydraulic Pump may be retained and the ACU200 will need to be replaced with an ACU400. However, should you find that the hydraulic cylinders have been plumbed in series, then the Type 2 Hydraulic Pump would need to be replaced with a Type 1 Hydraulic Pump and the ACU200 may be retained.

Q2. Vendor told me I needed this Type 2 pump due to the volume of the rams, so bought it with the EV-200 System. Made no mention of needing the ACU-400 system.
A2. Should an authorized Raymarine dealer have advised you incorrectly concerning these purchases, then it would be recommended that the Raymarine dealer be contacted to return these purchases to then permit the correct autopilot components to be purchased for this application.

Q3. Now I find out that recommended type 2 pump was wrong. So now looking for a solution.
A3. This is not necessarily the case ... see my response to Q1.

Q4. Can I use a non-Raymarine autopilot pump such as the Autopilot Pump for Ram Sizes 14 Cu In to 25 Cu In (PUMPHRP17-12)-which is for a Furuno system?
A4. Yes, However, like the ACU requirement for a Raymarine Type 2 Hydraulic Pump, an ACU400 would likewise be required for this third party hydraulic pump.

Q5. what risks do I run using this type 2 pump with the ACU-200 or going down to the Type one Pump with the ACU-200.
A5. When configuring the Evolution autopilot of a system featuring an ACU200, the system will only provide an option to select a Type 1 Hydraulic Pump. If it works at all (may report No Drive Detected or Overcurrent), the Evolution autopilot would drive the Type 2 Hydraulic Pump based upon the performance characteristics of a Type 1 Hydraulic Pump and the resulting autopilot performance would likely be adversely affected.

Q6. Changing to an ACU-400 is just not an option.
A6. Please see the response to Q1, as an ACU400 will only be required if the rams have been plumbed in parallel. Again, as the vendor may have advised you incorrectly, I would notify the vendor and give the vendor the opportunity to make it right.