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Trolling/slow speed drive/maneuvering ZF Gears

Discussion in 'Engines' started by Capt Maritime, Jun 19, 2022.

  1. Capt Maritime

    Capt Maritime Member

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    I am doing some research on the functions of the ZF 325-1A gears with trolling/maneuvering function. I have never had a boat with this option as its installed on the Cabo 40 Convertible coupled to CAT C-12's.

    Any feedback from the community would be helpful. I'm planning to practice how the boat reacts in both normal and maneuvering mode with plenty of room before I need it in a crowded marina.
  2. DOCKMASTER

    DOCKMASTER Senior Member

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    Bob - what engine controls and thus trolling function controls does your new boat have? I have the ZF 650 gears with the ZF controls. The trolling function works great if you need slower than idle speed. On my controls, when I go into troll mode the throttle lever now controls trolling speed. It does this by reducing clutch pressure via a bypass. It will go from zero clutch pressure which obviously means no shaft RPM, up to about 50 psi. For my boat, with only one engine running I get troll speeds from zero to around 3 kts. If you continue to apply throttle when in troll mode it will increase clutch pressure until you reach a point where the clutches fully engage and you are basically back to same as normal idle speed.
    Some guys like troll mode for slowing down in Marinas and docking. I personally do not like it for that as the reaction time is too slow for my liking. That being said, my marina is small so I have a very short trip to be out in the Chanel where we are allowed 7 knots until out of town.
  3. Capt Maritime

    Capt Maritime Member

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    The Cabo has ZF 325-1A gears. When I sea trialed her I did not get the opportunity to try the trolling function. The palm beach electronic controls are smooth. My previous Cabo had push/pull Morse type controls so for me the electronic controls, although a much improved option, will take some getting used to.
  4. Pascal

    Pascal Senior Member

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    I m not sure why you d want trolling valves to maneuver in close quarters. I ve never had them on any boat I ve run and don’t see why they d be needed. How long you remain in gear while maneuvering depend on the engines, props and boat weight. For instance with high HP boats you rarely stay in gear for more than a second or two while getting in and out of a slip. In the fairway if idle speed is too fast you just bump in and out of gear every 5 or 10 seconds

    don’t overthink it
  5. Capt Maritime

    Capt Maritime Member

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    For me it is just going to take some getting familiar with how the vessel responds. I just moved up from a 35 Cabo Express with a full tower and all mechanical controls to a 40 Cabo Convertible with electronic controls. As with anything new, it is just going to take some time for me to feel how this boat maneuvers and reacts to wind and current.

    For me being technical, I always want to understand the mechanics/functions of what is happening in the engine room vs ordered commands from the bridge.
  6. Slimshady

    Slimshady Senior Member

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    We have them on 60 sportfish with c18. When in troll mode the motors idle a little higher and the throttle required to produce propeller rotation is greatly exaggerated. For example, just engaging in low forward will barely produce any boat motion. Full throttle will produce about 7 knots. Normal in gear is 6.5 knots. Gives you great slow spead adjustment. We only use it when kite fishing or deep dropping. Docking transmission is at normal setting with quick bumps in and out of gear.
    As dockmaster said it adjusts oil pressure allowing slippage.
    Motor rpm stay constant.
    If you've had a sportfish before you'll find docking a bigger one is actually easier. They respond more slowly and predictably.
  7. Pascal

    Pascal Senior Member

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    I understand the need to understand but it s only 5’ and different controls. Don’t overthink it, you will
    Adapt without thinking about it. The bigger the boat the easier it is.
  8. Capt Maritime

    Capt Maritime Member

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    Sounds good. Thanks for the input everyone.
  9. DOCKMASTER

    DOCKMASTER Senior Member

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    On most electronic controls you can select the idle RPMs you want to have in troll mode. On my C18s I can select from 550 to 1000. 1k is max allowable rpm when in troll mode due to heat generated by clutches slipping. I use 550 rpm and only one engine but my situation is much different. This is for trolling for salmon with downriggers. I’m looking for 2.0 to 2.5 knots max speed. The higher end for Coho and the lower end for Chinook.
  10. mapism

    mapism Senior Member

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    Do you mean that half a knot can be relevant when fishing either one or the other type of salmon?
    Not a fisherman myself, but that sounds very professional!
  11. mapism

    mapism Senior Member

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    Much improved in which way, exactly?
    I mean, what are you expecting from them that your cable controls couldn't do?
  12. DOCKMASTER

    DOCKMASTER Senior Member

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    I agree, you are not a fisherman. :):)

    Half a knot may not sound like much but when you consider the main target is only 2 knots it’s a 25% difference. And when you are pulling different types of flashers or trying to get a certain roll on your bait it makes a big difference. And current plays a big roll in this as well.
  13. mapism

    mapism Senior Member

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    More than happy to take your word for it.
    I've only been out on fishing boats in a few occasions, and I'm pretty sure that the (professional) helmsman kept a much higher speed while trolling, anywhere from 5kts or so at "normal" idle, up to about 8 with a touch of throttles.
    Then again, that was for fishing tunas and mahi-mahi, which I guess makes a helluva difference. :)
  14. Capt Ralph

    Capt Ralph Senior Member

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    Different technique, different fish. Yes, A helluva of a difference.
  15. Capt Maritime

    Capt Maritime Member

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    As mentioned this is my first boat with electronic controls but not my first sportfish...Egg Harbor, Bertram, and now Cabo. As with anything it will take some getting used to. She's turning turning 26 X 32 four blade federal props via 2.5" shafts.
  16. Maxwell

    Maxwell Senior Member

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    I don’t have direct experience as our boat didn’t have trolling valves. Not sure why you’d use them around the dock anyway, but I always heard that it’s bad to, or you can’t use them in reverse. Can anyone comment on the validity of this?
  17. Slimshady

    Slimshady Senior Member

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    They work in reverse. They feel slow to respond which isn't the case.
    It takes exaggerated throttle movement to get the boat to respond because of the slipping clutch. That exaggerated movement very close to a dock or boat is unnerving.
  18. CaboFly

    CaboFly Member

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    Don't use trolling valves to dock. Not enough control and ability to stop the boat. Too much slippage. I use both engaged in troll mode to navigate a long no wake zone or to fish. For salmon on my boat it is one engine using trolling valve engaged and rudder at a 12 to maintain a straight course. Both engines in fwd with valves engaged is too fast. As was mentioned earlier 1.5 to 2 knots is the target.

    When docking set rudder to zero and bump in and out of gear. It takes getting used to on the 40. Boat handles great once familiar.
  19. Capt Maritime

    Capt Maritime Member

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    I had the opportunity to maneuver the boat on sea trials and yes she handles well. I was impressed on how easy she handled even with some wind and some current. Solid well balanced boat. I cant wait to get her home!
  20. GPO

    GPO Member

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    In my case, in close quarters I want my wheels to bite - with only bumps on the throttles. To me, having to use exaggerated throttle movements seems counter intuitive in careful close quarters manoeuvring. My Twin Disc Quick Shift transmissions have an express setting which I will not use in close quarters, much less the trolling valve setting.