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Full Version: [TG11] Retrofit or new autopilot?
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I have a 34' Silverton Convertible and recently installed an Axiom 12 MFD and
RD 424D radome.
It has a fully functional, but older, Northstar Autopilot. I want something that is integrated with my Axiom. I had an Evolution 100 Autopilot on my twin outboard 28' open fisherman and liked it.
Is there any part of this Northstar system that can be used with the Axiom or should I just buy a complete new Evolution for it?
That leads to another question. Will an Evolution 150 be OK? The description says it's good for small to medium boats. Boat size is pretty subjective. I guess to some people a 50' boat is small.
Hello Vettepro,

I assume the steering is hydraulic? If so, what we would need to know is the capacity of the steering cylinder (ram). This tells us what pump you need in order to get the right hydraulic flow rate for good steering performance (right pilot hard-over time). You could potentially re-use the existing pump, but to do that and be sure it was going to work well you would need to know both its peak stall current (not the average or running current you might see on the distribution panel ammeter, but the most the pump will draw when flat out) and that it has a specified hydraulic flow rate that is comparable to that of the pump that we would specify for your capacity of steering cylinder.
None of the rest of the pilot would be re-usable.

Once we know what sort of drive will be used, then that determines the ACU to use. ACU150 will do up to a Type 1 hydraulic pump for example, if you needed a T2 pump (because of the size of the ram) then you would need an ACU400. These details are on the pump page I linked to above. With hydraulic systems it's not about boat size or weight, it's all about ram capacity and fluid flow rate to achieve the right steering rate.

Is the cylinder volume something that is "usually" on a tag of some sort on the cylinder?
I confirmed the steering ram is 8.3 CID. I believe the best way to do this is to get the EV-150 pack, including the pump?
Yes, 8.3 cubic inches (roughly 135cc) is right in the middle of the range for a Type 1 pump, which means an EV-150 pilot. Our part T70330 is a complete kit including the pump.

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