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Thread: Question on replacement rudder

  1. #1

    Question Question on replacement rudder

    I ordered a dual outlet rudder a month ago. Long story short, they lost my order and ended up sending it from another warehouse that only took 2 days to get to me.

    The rudder I received seems way too long. So I thought it was the wrong rudder. The part number on the rudder is pb125. What I ordered was a pb126.
    I did some investigating and found out the pb125 is for a ProBoat 36” Voracity. So I contacted the seller and told them I got the wrong part.

    They informed me it should be correct and stated the pb125,pb126, and pb127 are all the same size.

    I measured the stock rudder at 4.385” long and the replacement as 4.920” and a lot wider. I expected more width due to the dual outlets, but that much more length in the water just seems excessive for a 30” hydro.

    Use it or not?
    Attached Images Attached Images
    Last edited by Hawcer; 10-28-2018 at 09:12 PM.

  2. #2


    So...should I run it as is, cut it shorter ( as the seller recommended) or return it and get one at OSE like I should have the first time?

    I honestly think they are trying to pass off carry-over parts from older models as direct replacements for newer boats.

  3. #3


    Just because I'm spoiled and impatient when it comes to my rc's I'd say if everything else lines up then just shorten the new one and finish the bottom of it as close as you can to the original..... LOL, That being said.... I've posted on here I'm a noob. and actually got answers on one of my posts... So I thought I'd offer mine in case no one smarter comes along... (Let's hope so).

  4. #4


    Yeah, I’m inpatient also and It always cost me more money in the long run.

    I measured the depth of the water passage through the length of the rudder and it is machined .185” deeper than the lowest inlet port.

    So if I cut off the rudder just below that point, I will only be removing about 1/4”. That little bit probably won’t make enough difference to go through the trouble.

    So I’m still on the fence. Try it the way it is(even though I’m sure it’s going to drag the speeds down) or send it back?

    For everyone else with a UL-19. Don’t order the dual output rudder from rcboatbitz unless you want an extra long rudder.

  5. #5


    I can't tell from your picture if your new longer rudder has enough meat to re-drill BUT I've run into a similar situation in a custom build where I wanted the beefy dual pickip SPD rudder shortened more than just trimming the bottom off right up to the water pickup. My solution was to re-drill and RAISE the rudder until I got the height where I wanted it. Worked for me

    rudder shortened.JPG
    2008 NAMBA P-Mono & P-Offshore Nat'l 2-Lap Record Holder; '15 P-Cat, P-Ltd Cat 2-Lap
    2009/2010 NAMBA P-Sport Hydro Nat'l 2-Lap Record Holder, '13 SCSTA P-Ltd Cat High Points
    '11 NAMBA [P-Ltd] : Mono, Offshore, OPC, Sport Hydro; '06 LSO, '12,'13,'14 P Ltd Cat /Mono

  6. #6


    I thought about that option too.

    If I use the lower mount hole as the top hole and redrill another hole for the lower(where the break-away screw goes). it will be about the same depth as the stock rudder.
    couple drawbacks:
    1. the lower hole will be in the blade area. not a huge problem since the upper bolt does most of the work.
    2. I would have to cut off the upper portion that would sit above the rudder mount to retain the break-away function.

    I made a deal with the seller. he gave me some money back since the rudder wasn't as expected. but the hose kit with all the correct fittings will work as needed.

    this rudder is made really nice and would sweet on a bigger deep V boat. It's a direct fit for a proboat Voracity.

  7. #7


    Again I know nothing so only an uneducated guess. I think the extra length will cost very little in drag and top speed. But I think that the more surface area of the larger rudder will give you more positive turning. The big question is, does your servo have enough torque to handle the forces on that larger surface....

  8. #8


    Quote Originally Posted by David Brock View Post
    Again I know nothing so only an uneducated guess. I think the extra length will cost very little in drag and top speed. But I think that the more surface area of the larger rudder will give you more positive turning. The big question is, does your servo have enough torque to handle the forces on that larger surface....
    I installed a 20g metal gear servo, it’s got the balls to swing it.

    As far as drag goes...
    If you ever clip some debri and snap the nylon rudder screw and the rudder gets knocked at an angle and has less rudder in the won’t turn for squat, but you’ll gain more top end speed.

    So a longer rudder will cause some extra resistance. I imagine the more “anything” on the boat that is in water will cause more drag.

  9. #9


    Like all setups for any race vehicle there will be compromises you have to choose. Like sometimes less above water wind drag is more important than down force. Or water drag vs ability for tight turns. Also moving weight forward makes the boat more stable but slower because there is more of the boat in the water. It's all about finding the sweet spot for you and the conditions you are running in as to where and how you choose to make those compromises...

  10. #10


    well, this RCBB rudder is on it's way to the new owner.
    I'll probably order the rudder for the Veles from OSE. it appears to be the same length as the stock rudder and they have plenty in stock. Unless the UL-19 rudder comes back in stock soon.

    The longer RCBB rudder probably would have worked...I'm just not in the mood to mess with it.I guess.

  11. #11


    Have read other articles and threads and now the manual (Got my brand new UL-19 Monday. I've decided I want to add another cooling line so that both the motor and esc have their own lines (Why release a bot with electronics that will over heat if used at full potential?!?!?!?!?). Hawcer, could you point me to the replacement rudder you got with the 2 water intakes? Or the right one since you received the wrong one Now do you think the rudder with the double intake is the best way to go? Or would be adding a water intake spout off the back of the boat away from the prop be an easier/better way to go?

  12. #12


    I got it on eBay, but here is a direct link to it on their website.
    The price seems practical until you get jabbed with the high shipping price....but it does come with the tubing and a couple fittings.

    Be aware, The rudder they have listed for the UL-19 is the same thing as what they have listed for the Veles and the least that’s what they told me when I assumed they sent the wrong one.

    I have one on the way from OSE that is listed for the Veles, but is pretty much the same length as the stock rudder, but with dual outlets.

  13. #13


    Cool, I'm already going to order this prop for my UL-19 on the recommendation of someone more experienced than me.

  14. #14


    David, I have that RC Boat Bitz dual rudder on both of my UL 19's and it is much larger but I can't detect any difference in speed vs. the stock one. I love it. I bought Hawcer's and have 3 of them now.



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