TomCat hydraulic steering: Series vs parallel.

Captain Starbucks

Brats,

I'm getting ready to install an autopilot on my 2009 TomCat. It's got twin manual Seastar helms, twin 150's with 8.3 cubic inch rams.

I was getting ready to order the parts I thought I needed but it became clear I didn't know enough about my system to know what to order.

I thought I had a series setup, but an image Simrad sent me suggests I *might* have parallel since my boats got twin manual hydraulic helms.

Any info appreciated.

Thank you,

Rob

Captain Starbucks · Posted: Thu Oct 03, 2024 12:28 pm Post subject:

I believe that even though my boat has two helms, it's got he liquid tie bar and should be series.

thataway · Posted: Thu Oct 03, 2024 2:34 pm Post subject:

To add to your diagrams, here is how the liquid tie bar--which shows the rams in parallel. The second helm will be also in parallel. Thus you need a pump for the ram capacity twice each of the rams--probably and EV-Type 2 pump. ((14 in3–21 in3) and ACU-400. Unfortunately this is not the minimal priced unit. (the type 1 is usual on a single engine, with the smaller ACU.). Se the second link for the ram size and motor size, plus diagram of the liquid tie bar.

Dometic bought Sea Star Teleflex. The good news is that their technical rep is often present on The Hull Truth. Here is a thread where "Dometic Marine" here is a thread where Dometic Marine technian comes up to answer a question. You can send him a PM or email.

How to select the Best Auto pilot (RayMarine).. If you want Garman or Simrad the sizes of pumps and drivers will be approximately the same capacity (not getting by with the cheapest components), as if you had a single 150 or 90, or two 40's. The 90 will still take the 150 system, but with 8.3 ram capacity.