17-24'

17-24' Forums

  • Boating General Talk Forum
    Rhodan Trolling Motor / V-Anchor System Gearbox Issues - 13 Feb, 2019

    I have one of the first 84” shaft 36V Rhodan V-Anchor systems on a 28’ Americat Gen 2 catamaran and while I love the unit and its functionality and can honestly say it has increased out catch rate when bottom fishing by allowing us to hold position right on top of the fish it also has some deign issues.  

     

    The unit has been installed for two years and I am installing my 4th replacement gearbox.  All the failures have been exactly the same.  The fiber/nylon/plastic (unsure of the exact material, will call it plastic for the remainder of the post) gear that functions to steer the motor becomes stripped by the brass gear on the steering motor shaft. 

     

    We do not fish the motor in bad sea conditions, nearly always 2’ or less so I do not believe the issue to be an application issue but rather a design flaw that is amplified by the leverage forces of the 84” shaft.  The hollow plastic gear that the shaft runs through is mounted in the gearbox via a plastic bushing on the top and bottom of the gearbox case and these bushing have an O-ring on them.  I believe the forces on the shaft are allowing movement in these bushings that in turn allow enough movement in the plastic gear to cause slippage and wear on the plastic gear finally resulting in failure of the units steering.  I believe there are two other compounding issues; the small DC motor mounted in the gearbox is held in place with 4 SS Philips-head screws that run through a mounting plate.  The holes drilled in the mounting plate are larger than the associated screws which over time can allow for a small amount of movement in the mounting plate also permitting the gears to slip.  This could be helped, I believe, by changing these four screws to SS Allen head screws and using Loctite to really torque these screws down and prevent this movement.  Finally, the two halves of the gearbox are in no way keyed and the two haves are held together by four screws.  Because of the lack of keying these two halves could have movement in them if these screws were to work loose.  Having said that these screws (unlike the motor mount screws) are Allen head and mounted with Loctite from the factory. 

     

    Rhodan has been great about replacing these gearboxes so far but our warranty will end this spring so we’ll have to see what happens with the next failure.  I would like to see them address these issues in the design and tighten the tolerances in this critical component. 

     

    Is anyone else seeing gearbox failures?  

     

    Tight Lines