Trim Tabs on a Thunderjet

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by grizzly king, Jan 30, 2018.

  1. grizzly king

    grizzly king Member

    Looking to add trim tabs to my Thunderjet 20' Chinook. It has a split engine platform so installation of trim tabs might be difficult where the platform drops. Im looking for suggestions on what type to buy and if there are any Thunderjet owners out there with a similar boat, how did you get around this issue?
  2. GLG

    GLG Well-Known Member

    I had a 19.5 duckworth that's similar to your boat. When I got it the starboard side would ride slightly higher then the port side when on plane. I fixed that by bending down the portside trailing edge of the hull back at transom. It only needed maybe a 1/8 to 1/4 inch from where it was to fix that. I used a piece of angle iron and two big crescent wrenches to "tune the hull". I also swapped out the 3 blade prop for a 4 blade prop and that fixed the lack of trim that I found on my design. I used a Turning Point Hustler that advertises to have stern lift and that worked wonders. It fixed my trim issue and when on plane changed the attack angle giving me a better ride.
  3. alumaman

    alumaman Active Member

    You shouldn't need trim tabs on your thunderjet. Call or send a message to the factory and they can advise you how to address the issue. GLG is right about adjusting the trailing edge adjustment. I had to do the same to both aluminum boats I previously owned.
  4. JAC

    JAC Well-Known Member

    I had a 2014 thunder jet chinook. Trim
    Tabs made a world Of differents . I ran the 12” Lenco tabs they were great and easy to install
  5. grizzly king

    grizzly king Member

    The tabs are necessary for once I start loading guys and gears my boat gets out of wack.
  6. JAC

    JAC Well-Known Member

    I used it to trim the bow down in the chop it really helped with that
    Gunsmith likes this.
  7. mbowers

    mbowers Active Member

    Some pics would help understand the details of your situation. Bennett has many different options for tight spaces that might not show in a quick search. If you get no answers here, call them or post in a forum that Tabman (factory) frequents like The Hull Truth.

    I like big tabs placed way out to the sides so you get maximum adjustment.
    kaelc likes this.
  8. bpsuls

    bpsuls Member

    I have a Hewes OP and the trim tabs are pretty critical IMO. bending the leading edge is great for a constant load balance issue but wont help for dynamically changing boat loads. Asking people to move around and moving gear around while underway is annoying when all you need to do is just push a button and it corrects it. I have the Lectrotabs, which have a lifetime warranty on the units. I like them because they are not hydraulic, so setup is simple and takes up barely any room. I have the electronic controller so when you shut off the engine it resets the tabs to their contracted position automatically. They will save you fuel over time and when it gets really choppy they help make the ride much smoother.

    Cannot speak for the install challenges on the T-Jet though. best of luck to you.
  9. grizzly king

    grizzly king Member

    This is not my boat but here are some pics. You can see how the starboard side of the engine platform is split and as a result the trim tabs on that side would probably be mounted to the hull under the waterline. That is my pressing issue with the installation.

  10. kaelc

    kaelc Well-Known Member

    You should sell the boat to me and buy something with room for trim tabs :)

    If you have the lip that runs about an inch past the bottom of the transom Bennett will modify your tabs free of charge so they mount on that lip, not on the transom, which may help with space. You have to courier your tabs to them but if you have a buddy in the US or are down for a few weeks vacation it is pretty cheap.

    Ever look at adding a fin/hydrofoil to your main? It doesn't help with balancing a load but when my boat was loaded with guys and beer it performed way better with the SE Sport 300 and you can add it without drilling into your awesome Yami!
  11. JAC

    JAC Well-Known Member

    Easy to install yourself i did mine in about 6-8 hours taking my time. I went to a thunder jet dealer and took some pics of the factory installed ones. They used Lenco tabs at that time anyways don’t know what they use now electric are easier to instal then hydraulic.
  12. mbowers

    mbowers Active Member

    Below waterline is fine for the tabs / actuator as everything is waterproof but the tab must be above the bottom corner of the transom so it does not drag when retracted. Might need to cut a slot in that swim platform for the actuator..

    Tabs are awesome once you learn how to use them so I hope you find a way. I like an indicator gauge so I always know where the tabs are.
  13. grizzly king

    grizzly king Member

    Since the trim tabs are stainless and I will be running the boat in salt water, should I put zinc on them to help prevent electrolysis? I have been advised to do so by some and others said let the boats zinc to the work for you. Suggestions?
  14. saanauk

    saanauk Active Member

  15. grizzly king

    grizzly king Member

    Thunderjet headquarters told me what to do and what to install. Lenco 9x12 standard. They were great to deal with but I did not ask them about adding zincs the tabs.
  16. Franko Manini

    Franko Manini Well-Known Member

    Grizzly King,

    What did they tell you to do? I can see having the tabs mounted to the trailing edge, but where do you mount the actuators?
  17. SteelyDan

    SteelyDan Well-Known Member

    Friends of mine that fabricate aloy boats do a turn buckle type welded aluminum trim tab. Located in Mission. PM me if you would like contact info.
  18. grizzly king

    grizzly king Member

    They told me to cut a small hole in the platform so that the actuator has room to get through. They also told me to use lenco standard 9x12 trim tabs
  19. grizzly king

    grizzly king Member

    So I am trying go install these tabs under the recommendation of the professionals and am experiencing issues. The actuators mount8ng location is a real pain. One boat mechanic suggested installing the plates then mounting the actuators off centre. Not using the factory holes. Do you think that this a feasible option.
  20. casper5280

    casper5280 Well-Known Member

    I would think that if it's moved sideways a small amount it shouldn't be to bad, but there is a lot of force put on them. Would moving the actuators up help? You could put a small block between the actuator/trim tab thus moving the upper actuator mounting point up and not affecting it.

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