Helm pump

Discussion in 'OnBoard Electronics & Controls' started by ben2go, Jun 26, 2019.

  1. ben2go
    Joined: Jul 2008
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    Location: Upstate, South Carolina,USA

    ben2go Boat Builder Wanna Be

    I've been reading, a lot. In preparations for building my boat. In one of Buehler's books, he mentions using off the shelf industrial/commercial parts to build the steering system. This past week I have been educating and researching what I need for my steering. I nearly fainted like a sissy when I saw a 2.0 cubic inch helm pump runs $1500+. Throughout my research, no one has mentioned the type of pump that it is. I can't seem to find anything similar to a helm pump that will work. I will be doing in shop research next week, I hope to question a few hydraulic guys about these pumps. When I drove and worked on forklifts, they used them. I never replaced one. I only replaced the lines on one. So my question is, what type of pump is a helm pump?
     
  2. Barry
    Joined: Mar 2002
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    Barry Senior Member

    1500 is pretty high,
    A basic Seastar/Baystar helm pump is about 500 give or take and has a standard tapered shaft to accept a wheel.
    An advantage is that they usually have the two way system check valves so that there is no feed back creep due to forces from the ram.
    Are you trying to turn an outboard, or rudder or?
    I imagine that Craigs List has them on cheaper, or find one used,

    I doubt that you will save much by sourcing out another style pump. The helm pumps and rams are built for sea water exposure, something you may or may not get on an "off the shelf"

    Most forklifts run off the hydraulic pumps for the main mast ram, I don't think that I have ever seen a manual set up mainly because the pressure is already in existence and if you
    have several hundreds pounds or more of counterweight over the steering axle, it would be difficult to turn.
     
  3. ben2go
    Joined: Jul 2008
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    Location: Upstate, South Carolina,USA

    ben2go Boat Builder Wanna Be

    It's a 28' cabin cruiser with a Beta 38 diesel inboard, full displacement hull (17,000lbs roughly) with a 16 x 24 plate rudder. I just need to know what type rotary pump helm pumps are. I am making my own 18-inch wheel with either a 3/4 or one-inch adapter with a 1/4" keyway. The helm pump will be tucked away inside the nav station. If it gets sea water to it, I may have bigger problems.
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

  5. ben2go
    Joined: Jul 2008
    Posts: 183
    Likes: 4, Points: 18, Legacy Rep: 13
    Location: Upstate, South Carolina,USA

    ben2go Boat Builder Wanna Be

    The system has already been sized doing the fluid calculations. I need to know what type of pump a helm pump is. I know it's a rotary pump with check valves that allow fluid to only run one way at a time.

    The system you link to is for an outboard. It will not work for my set up.

    My system is designed for a non pressurized 2 cubic inch pump, with a 1.5-inch x 8-inch double acting hydraulic cylinder, and requires 3/8-inch lines with SAE #6 fittings. This will give me 5 to 6 turns to move the rudder through a 90-degree arc using a 16-18 inch wheel and a 6-inch tiller arm on the rudder.

    I finally found one name for it, steering orbitrol unit AKA orbital control hydraulic pump. There is another name for it but I can not think of it or find it.
     
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The helm pump in the link will work with a variety of ram configurations. The only difference between the outboard and inboard rams is the mounting configuration. The link has a good explanation and an exploded view of the interior of a pump. I understand building things as a hobby, because it is really satisfying. However, it is not going to be cheaper and may not work properly. Look at the exploded view to see how complicated the system is. I am a mechanical engineer and shipwright, and would buy a complete system for the savings in money and time.
     

  7. Barry
    Joined: Mar 2002
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    Barry Senior Member


    The Seastar helm pump appears to be a Bent Axis hydraulic pump ( within the Axial Pump family) . A disc, operates on a system of small pistons pushing them in and out to create pressure as the wheel is turned.

    Google Seastar Helm Pump rebuild and there are quite a few links to show the internal workings of this type of pump.

    Your comment that the pump will be under cover and hence not subject to corrosion/rust. Certainly the marine helm pump and motor might be more expensive than an off the shelf
    pump that you may find at a bargain source but for the most part most pumps for the marine industry will use corrosion resistant material, such as aluminum bodies, brass/bronze/stainless
    components where they are exposed to a corrosive high humidity atmosphere. Having owned ocean boats since about 1980, and all with a Seastar/Baystar style hydraulic steering systems the only issue that we have had was to replace the seals on the marine ram, stainless piston, aluminum cylinder etc, in a boat that was about 25 years old. EXCEPT that some
    less than intelligent person, or driven by what he had on hand, screwed a STEEL street L into one port of the ram which was rusted so bad that it had to be removed by drilling and using an easy out to get the threads out.
    If long term reliability is one of your goals, a good choice would be marine components for your steering.

    Your comment that the system that another contributor provided that the system was for an outboard. It is easy to source through marine stores various cylinders to actuate your rudder.

    Also note that the helm pumps almost always have a fill fitting at the top of the helm to make filling and bleeding an easy option.

    Additionally, the configuration of the helm pump provides a bit of a reservoir, ie the inlet to the pump is submerged in extra oil so that if you do develop a leak over time, and the level drops, you will not instantly lose hydraulic pressure to the ram. You may be able to rig something up to duplicate this advantage, but at further cost
     
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