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Thread: Fixing the BJ26 Handling Issues

  1. #1
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    Default Fixing the BJ26 Handling Issues

    The main purpose of this thread is to help owners of the BJ26 deal with the poor handling the boat has out of the box and to provide a thread where everyone can post what mods they have done to improve their boats handling. I will now list and discuss what I have learned here on the forums and done to make my boat handle much better.

    First, the problems with the stock setup:

    The turn fins are set up like on a mono hull and cause the boat to list or roll over when turning.

    The batteries and brushless esc are too high off the bottom of the hull which adds to the listing by making the boat too top heavy.

    The steerable drive system actually accentuates the listing by pushing the boat over on it's side when attempting to turn sharply resulting in flipping the boat over.


    Fixing the stock setup:

    The turn fins:

    I have tried the BJ26 both with the fins on in the stock position and with the fins off the boat. With them off, the boat turned better but felt too loose on the water and it still flipped over when making high speed turns and very low speed turns. The following mod has made the most positive affect on the handling of my boat out of all the mods I’ve made.

    BJ angled turn fin 01.jpg BJ angled turn fin 02.jpg BJ angled turn fin 03.jpg BJ angled turn fins 04.jpg

    The turn fins on outboard tunnel hulls, hydros and riggers are all angled to help suck down the inside sponson to keep the boat planted in the turns. The BJ26 turn fins need to be angled inward at the bottom to keep the boat from listing and keep it planted. As you can see in the pictures I have angled the fins to match the lower part of the outside of the hull. I have also raised the fins using the upper mounting hole for the lower mounting point and then leaning the fin over to get the right angle. This leaves about ¾ to 1 inch of the fin below the bottom of the hull. This has worked great on my boat but you may need more angle depending on your setup especially if you are using the stock drive. Note it is important to shorten the amount of fin that’s in the water or the boat will shimmy in the turns on it's fins. Also you will need to move the center of gravity about 1 inch further back in the boat to get the full benefits of this mod.
    Last edited by PropNutt43; 04-12-2008 at 12:10 PM. Reason: change font

  2. #2
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    Lowering the batteries and esc and changing the center of gravity:

    I have removed the battery trays and radio box to reposition the batteries and brushless esc as close to the bottom of the hull as possible. This helps reduce the top heaviness of the boat and improves its handling.

    BJ setup 01.jpg BJ setup 02.jpg

    I used some thin Styrofoam and Velcro to do this. As you can see the batteries and esc have been moved to change the center of gravity further back in the hull. The batteries are about 3 inches back from the stock position. This has moved the CG back about an inch from the original location. From the back of the boat the CG is 6.75 inches.

    BJ CG 7.75in 01.jpg BJ CG 6.75in 02.jpg
    Original location ... 1 inch back
    Last edited by PropNutt43; 05-09-2008 at 10:13 PM.

  3. #3
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    Steerable drive system:


    I have replaced the stock drive system with Fullers Catamaran Hardware
    This drive works excellent especially if you want the BJ26 to turn well both left and right. I have run this setup with the stock motor and brushless esc with the stock prop also with an octura X642 and X442 both detounged. So far I like the performance of the X442 best. Depending on which prop you use you will have to adjust the height and angle differently.

    BJ Fuller Cat Hardware 01.jpg

    If you are going to stick with the stock drive system after doing these mods please post your performance results. It would be interesting to know how well they work with that setup.

    Please remember all these mod locations and positions are starting points. You will need to fine tune them for your boat's setup.
    Last edited by PropNutt43; 04-12-2008 at 12:06 PM. Reason: change font

  4. #4
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    Great job. I am interested in trying these mods.
    1. Can you explain how you cut and upgraded the flex cable tube and what parts you used?
    2. Did the fullers hardware come with the secondary water pickup? I noticed the turn fin has one built in. It seems like the turn fin pickup might cause unnecessary drag if not used.
    3. Looking at the rear of your boat there is a black knob or something just to the left of where the water pickup tube enters the hull. What is this knob?

  5. #5
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    #1:
    The Fullers cat hardware can be used with the stock stuffing box tube with no mods, but you need to ask for a .150 flex shaft and liner with 3/16 stub shaft in the notes when you order it. You will also need to cut the flex shaft to the right length and solder the end so it won't fray. This cat hardware comes with almost everything needed, but you will have to make a longer steering rod to reach the rudder. The mounting bolt pattern is longer top to bottom but the width is the same so you will need to drill two new mounting holes in the hull. I used the top two holes and made two new holes for the bottom.

    http://www.drcwebservices.com/ffe/

    The only reason my stuffing box tube looks different is because I removed it so I could make it flush with the bottom ride surface of the hull. This allows for better prop angle adjustments and causes less drag in the water.

    #2:
    I made the water pickup from copper tube and copper strip soldered together. I just prefer the extra flow pressure from the prop to keep things cooler. Have had no drag problems from rudder the way it is.

    #3:
    The knob is a push-pull remote switch for the boats esc. It makes it a little easier to turn it on – off after the hatch is taped down.

    http://www.offshoreelectrics.com/products.php?cat=73
    Last edited by PropNutt43; 01-04-2011 at 08:05 PM.

  6. #6
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    Had a little more time to run the BJ26 on the weekend. Did some more experimenting with the turn fins and center of gravity. Started by adding more inward angle to the fins. This had the negative affect of lifting the outside sponson too much causing the boat to be unstable when making hard turns at high speed. Don’t recommend it .Went back to my original angle of matching the the fins to the lower portion of the side of the boat and everything was fine. Next started trimming the fins down a ¼ inch at a time. The shorter they got the more stable it turned. They now measure just under ½ inch below the bottom of the ride surface. The CG has been moved back another ¼ inch it’s now 6.5 inches from the back of the hull. Was achieved by moving the batteries an additional inch back which is 4 inches back from stock location. After these adjustments the boat is handling better and has picked up some speed due to less drag from the shorter fins and getting more air under it from moving the CG back. All in all it was a good weekend but I won’t be completely happy till I get this thing to turn like is on rails.
    Last edited by PropNutt43; 04-12-2008 at 12:02 PM. Reason: change font

  7. #7
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    The knob is a push-pull remote switch for the boats esc. It makes it a little easier to turn it on – off after the hatch is taped down.



    That's what I thought that was and I need to do the same thing on mine.Did you just modify the stock switch ?

  8. #8
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    I'm pretty sure it is this one. http://www.offshoreelectrics.com/pro...hp?prod=dh-203
    Anyway, my Fullers hardware is on order along with an x642 prop sharpened & balanced and 2 sets of (2) 2s 4800mah lipos. This is becoming quite expensive. Once these accessories arrive I should be around $900.00.
    Half on batteries, the charger and charger accessories, the other half for the boat.

    $285.00 - Blackjack Brushless
    $260.00 - (4) 7.4V 4800mAh Lipos
    $150.00 - Hyperion EOS0606i Charger
    $100.00 - Fullers Hardware
    $ 35.00 - Octura x642 Sharpened & Balanced
    $ 25.00 - Lipo Sack
    $ 20.00 - BL ESC Programming Module
    $ 20.00 - y-harness w/ balancer cables homemade
    $ 4.00 - Antenna
    Last edited by jaybirdtke; 04-08-2008 at 08:03 AM.

  9. #9
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    Yes, that is the exact same one. You do not need to modifiy the switch, it just bolts on. Every hobby shop I've ever been to has them or you could order it.

    http://www.offshoreelectrics.com/pro...hp?prod=dh-203


    BJ Remote Switch 01.JPG BJ Remote Switch 02.jpg BJ Remote Switch 03.jpg
    Last edited by PropNutt43; 04-10-2008 at 06:29 PM. Reason: add pics

  10. #10
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    Default Stuffing Tube Replacement

    Thanks for the great thread.

    Could you describe in detail how you replaced the stuffing tube and show some pictures of your installation.

    Thanks

    Regards
    Larry

  11. #11
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    [/QUOTE]

    $285.00 - Blackjack Brushless
    $260.00 - (4) 7.4V 4800mAh Lipos
    $150.00 - Hyperion EOS0606i Charger
    $100.00 - Fullers Hardware
    $ 35.00 - Octura x642 Sharpened & Balanced
    $ 25.00 - Lipo Sack
    $ 20.00 - BL ESC Programming Module
    $ 20.00 - y-harness w/ balancer cables homemade
    $ 4.00 - Antenna[/QUOTE]
    Dude,I ry to not think about it. lol

  12. #12
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    Relocation of Stuffing Box Tube:

    Removing Tube:

    It is pretty easy to do. First use an exacto knife to cut along the tube under the boat and inside the boat to break it free at the back of the hull. Make sure not to remove too much under the tube and inside the hull so it will be easier to reinstall. Once it's broke loose at the back just twist it to break it free at the front mounting point. No cutting necessary there which makes it easier to reinstall it later. Once everything is loose just twist it back and forth and pull it out the back of the hull.

    Refitting Tube:

    Scrape the tube off and sand to remove excess paint and fiberglass. Then file and sand the piece that the tube mounts to at the bottom of the hull till the stuffing box tube fits even with the bottom of the hull. The tube will need to be fit a little further to the front of the boat to get it at the right height. Doing this will keep it lined up with the motor at the right angle so it won’t bind. Make sure it fits flat on mounting surface with no gaps. After fitting it remove from hull and cut about ¼ inch or so off the front end so it won't hit the motor.

    Reinstalling Tube:

    When you’ve got the tube fit where you like, reinstall it with the plastic liner inserted and with the flex shaft connected to motor. Make sure everything fits right and there is no binding or misalignment with the motor. When it's ready use some CA to tack it in place. After it dries use 30 minute epoxy to finish the job and make it water tight. At the front mounting point I only used CA because it still fit tight.

    Cleanup and Paint:

    When the epoxy is dry sand and paint. I know mine looks a little ruff under the hull but I was in a hurry to get it back in the water. Will clean it up a little better later.


    BJ stuffing box tube 01.jpg BJ stuffing box 02.jpg BJ stuffing box tube 03.jpg BJ stuffing box tube 04.JPG BJ stuffing box tube 05.JPG
    Last edited by PropNutt43; 05-09-2008 at 10:39 PM. Reason: rearrange for clarification

  13. #13
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    $285.00 - Blackjack Brushless
    $260.00 - (4) 7.4V 4800mAh Lipos
    $150.00 - Hyperion EOS0606i Charger
    $100.00 - Fullers Hardware
    $ 35.00 - Octura x642 Sharpened & Balanced
    $ 25.00 - Lipo Sack
    $ 20.00 - BL ESC Programming Module
    $ 20.00 - y-harness w/ balancer cables homemade
    $ 4.00 - Antenna


    [/quote] Dude,I ry to not think about it. lol [/quote]


    I know this all adds up to a lot of money and even I'm on a budget. I got my boat last year in November right as winter was starting to hit hard. Didn't have much time to run it cause of the ice and snow. What I'm getting at is I didn't do all these mods at once. This is an ongoing project, just taking it a little at a time. That way it’s not so hard on the wallet and by doing it this way I have more appreciation for the benefits of each mod. Hope you don’t give up on this boat because it’s got a lot of potential.
    Last edited by PropNutt43; 05-09-2008 at 10:44 PM.

  14. #14
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    My Fullers hardware arrived along with the x642 prop. I got it all installed and there is noticable improvement to the turning ability. I will be adding a different type of water pickup, as you did, because I would prefer having water flow while making lefts as well as right turns. I'm still waiting on my lipos.
    I plan on running it again with the new hardware and stock prop as a comparison to make sure I didn't loose any speed with this hardware.
    What diameter is the copper stuffing tube that you used? or did you reuse the original stuffing tube?
    What diameter is the plastic tube that's inside the copper tube? Did you reuse the plastic tube that came with the flex cable?
    Thanks again.

  15. #15
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    The stuffing box tube is the stock one that comes on the boat. I just removed it cleaned it up and relocated it. The whole secret is to fit it at the bottom so you can slide it forward and keep the same angle the tube exits the bottom of the hull. By sliding it forward it will automatically bring it up to where you want and keeps the flex shaft from binding at the motor. You shouldn't have to add much bend to the tube if any at all when you fit it this way. The plastic liner is the one that came with the Fullers Cat Hardware. You will have to cut it to fit.

    One other thing I should mention before you do this mod. It will affect the way the boat handles. The little bit of the tube dragging thru the water in the stock position helps the boat track a little straighter. After moving it the boat will also be a little looser in the turns but not much. I had to put a little more prop in the water and move the CG back to counter this.
    Last edited by PropNutt43; 04-13-2008 at 03:36 PM. Reason: rearrange

  16. #16
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    Finally got around to cleaning up the stuffing box tube at the bottom of the boat. Here's what it should look like after cleanup and when it's done.

    BJ Stuffing Box Cleanup 01.jpg BJ Stuffing Box Cleanup 02.jpg BJ Stuffing Box Cleanup 03.jpg BJ Stuffing Box Cleanup 04.jpg

    Got another cold front moving in probably won't get to run much this weekend. In the 30s right now and expected to drop with some rain/snow? Crazy Midwest weather. Guess I'll just work on the boat some more.

  17. #17
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    On one of the picture of the inside of the boat a few posts back showing the on off switch it looks like you coated the entire interrior of the boat with something. If so why and what did you use to do it.
    Thanks

  18. #18
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    I believe you mean this pic.

    BJ Remote Switch 03.jpg

    What you see is 30 minute epoxy coating the transom at the rear of the boat. I have drilled more than a few holes in the transom and had too removed some of the wood that doubled up the thickness where the turn fins were originally mounted.

    Reason for coating:

    Wanted to waterproof the areas that were no longer coated in fiber glass. Also to strengthen around the edges and areas where the turn fins and drive hardware are mounted. You can see it better in this pic.

    BJ stuffing box tube 04.JPG

  19. #19
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    I now have 5 runs on the new hardware and it is awesome with the x642 prop and (2) 2s 4800mah lipos. The only mods that I didn't do is the stuffing box tube relocation, I left the original battery box locations and I haven't installed the external battery switch. I think I'm getting some water in the hull from the inside of the stuffing box tube where the flex cable exits to attach to the motor. I've sealed the antenna hole and I tape the hatch before every run.
    Aside from keeping the flex cable well greased how can I reduce water from entering here. It looks like you have some fuel tubing on the inside of the stuffing box tube. Is that what it is?

  20. #20
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    What tape is best used for sealing the lid , any pics .Thanks

  21. #21
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    Quote Originally Posted by jaybirdtke View Post
    Aside from keeping the flex cable well greased how can I reduce water from entering here. It looks like you have some fuel tubing on the inside of the stuffing box tube. Is that what it is?
    Yes, I used some 1/8 inch (3mm) silicone fuel tubing. It works great keeps the water out completely. only want about 1/8 " to rub against flex shaft and make sure a little grease gets in it to reduce friction.

    BJ Flex Shaft Seal 01.JPG

  22. #22
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  23. #23
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    Quote Originally Posted by dendrobate View Post
    What tape is best used for sealing the lid , any pics .Thanks
    This hatch tape from Fullers works great. It's at the bottom of the page.

    http://www.drcwebservices.com/ffe/hardware.htm

  24. #24
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    I need to replace my flex coupler. Horizon has it for $20.89. http://www.horizonhobby.com/Products...ProdID=PRB3308
    I searched Offshoreelectrics but couldn't find one that would fit. Can someone insert a link to a coupler from Offshore that will work?
    -----------------------

    Steve was nice enough to inform me that I would need the octura 5mm to .150 flex hex. Thanks Steve.
    Last edited by jaybirdtke; 04-14-2008 at 07:09 PM.

  25. #25
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    The one you need is on this page but looks to be out of stock right now. Octura makes Two couplers from 5mm to .150 cable. You want the short version (24mm) or you will have problems with the fit.

    http://www.offshoreelectrics.com/products.php?cat=68

    Fullers site has them too but make sure it's the short version before you buy. I would call to make sure.

    http://www.drcwebservices.com/ffe/hardware.htm
    Last edited by PropNutt43; 04-14-2008 at 08:16 PM. Reason: link correction

  26. #26
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    hi everyone. i just recently picked up a blackjack and it had two autobailers installed aswell as a CF45 prop and it was almost un driveable. it would torque twist and almost flip it self at full throttle on a straight line turning was near impossible at any speed. i removed the bailers and angled the fins which helped alot. i took 'er out today along with my SV and DAMN! what a quick boat! in the straights it would rip past my SV with a CF48, i took great care in the turns but did flip her when i came to a stop then attempted to turn from a dead stop..hit the throttle about 1/3 and over she went faster then i knew what had happened.

    im going to lower the batteries tonight but can anyone tell me which angle the set the drive to to possible help? up or down?

  27. #27
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    Have a look at this thread, it should help you out with prop angle and drive set up.

    https://forums.offshoreelectrics.com/...ead.php?t=3105

    Definitely lower the batteries and put the esc at the bottom of the hull too, if it isn’t already there. Every little bit helps.

    Sounds like you bought a modified version of the boat. Some pictures and more info would help.
    Last edited by PropNutt43; 04-17-2008 at 10:56 PM.

  28. #28
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    no, the only mods were the auto bailers that had about a 1/4" difference in height where they were drilled into the transom, a spektrum hi torque servo and a 3" pink antenna tube. Then there was the mods UPS put into the hull in shipping...separated the front end halves, destroyed the stock prop and put a nice crack on the top of the hull. pics would be nice huh! i cant find the damn charger for the camera. ill look for it today. i gotta take pics to put in a claim w/ UPS aswell

  29. #29
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    Sorry to hear about the damage from shipping. Hope you get a new boat out of UPS or at least a hull and prop.

    I thought the boat might be modified because of the way you said it was torque twisting on a strait line. Was thinking maybe too much motor.

    But if it's all stock the prop maybe angled up too much at the back, or too high above the ride surface which would also explain the boat wanting to blow over.

    Try straitening the prop angle out first and if that doesn't fix it lower the drive a 1/16 inch at a time till you get the result you want. The boat might lose a little speed but should become a lot more stable.

    As far as steering with the stock drive hardware, my boat didn’t turn well at very low speeds or high speed. It liked it best some where in the middle. Also turning the duel rate down on the radio transmitter helped by not allowing the boat to turn too sharp.

  30. #30
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    ok, update on my situation.
    I took the BJ out this AM.
    tried adjusting the trim angle with negative results on moving it down. for every slight angle adjustment i also tried moving the batteries fore and aft. So far it ran best with no turn fins prop angled all the way up and batts about 3.5'' back from stock. This improved turning ability but she still lists to one side and with 3/4 to full throttle she just starts turning leaning harder and harder. Im thinking maybe the CF45 prop might have somthing to do with it, all the props in your guys pics have a much deeper pitch the blades are more horizontal.?

    when i bought this boat i envisioned dual counter rotating outdrives. would that fix the twisting problem do you think? Has anyone else had this or similar problems with their BJ26?

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