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Thread: Let's talk trim tabs

  1. #1

    Default Let's talk trim tabs

    I've been looking at installing trim tabs on my boat. It porpoises a bit until I get up above 35 kts. I've been looking at the Bennett bolt tabs in 12x12 as with my twin engine it doesn't leave much room. I may not be able to fit a 12" wide tab and keep the manufacturers recommended 8" from centerline of engines. Would the 9x9's be adequate? My bottom already extends out 5" from my transom. I believe that is why it flattens out at higher speeds. I'm looking to get the bow down more for ride and porpoising. Any insight would be great. I feel like I may be able to get away with the 9x9 tabs due to the bottom already being extended back which will continue to help at higher speeds. Thoughts?

  2. #2

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    Boat is a 25' safeboat defender with twin 250 suzukis

  3. #3
    Member Akgramps's Avatar
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    I cant help you on the size, but you might look at Lencos, they are electric, so faster and no potential leaks or pump failure.
    I am sure Bennetts are excellent and they are common, but if buying new you might look at others.
    “Nothing worth doing is easy”
    TR

  4. #4

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    Quote Originally Posted by Akgramps View Post
    I cant help you on the size, but you might look at Lencos, they are electric, so faster and no potential leaks or pump failure.
    I am sure Bennetts are excellent and they are common, but if buying new you might look at others.
    The bennett bolt trim tabs are electric.

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    Quote Originally Posted by AKBroncoII View Post
    The bennett bolt trim tabs are electric.
    I didnt know that, I am sure they are good units. I see they make a conversion kit for the old hydraulics as well.
    “Nothing worth doing is easy”
    TR

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    before buying the tabs take some 1/4" nylon rope and stretch it as tightly as you can get it under your transom, it will act as a trim tab so you can see what tabs might do for your boat. Since your boat is outboard powered be careful of the rope coming off and winding up in your prop/s.

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    Member akfisherman's Avatar
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    I just put a set of Bennett sport tabs on my boat and I couldn't be happier


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  8. #8

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    I'm more worried about size as most say they are for specific sized boats. As in the 9x9's are for smaller boats. I would assume they would still work for me but just not give it as much lift as the larger tabs.

  9. #9
    Member akfisherman's Avatar
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    Take a look at the new sport tabs by Bennett. They are designed a bit differently and provide more lift


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    Member Akgramps's Avatar
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    This is a RIB....? Have you called safe boats and asked them what they recommend....?
    “Nothing worth doing is easy”
    TR

  11. #11

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    Safeboat is about worthless to call and ask anything. Took me two weeks to actually talk to someone last time whom could get me the information I needed.

    Which sport tabs tabs did you end up getting? I'm not certain as to why or how the sport tabs would allow for better performance. Do the wings just allow better deflection of water to push straight down instead of rolling off the side of the tab like a normal one? I have room for a 10" tab max. I have little transom space to not affect the prop.

  12. #12
    Member akfisherman's Avatar
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    I suggest you visit

    http://www.bennetttrimtabs.com

    They have lots of info on their website


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  13. #13

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    I want more real boater experience. I've already been in direct contact with bennett. It does me no good for a guy to be sitting at a computer answering emails with no real world experience of boats or their own product other than videos. I want real world feedback and experiences.

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    Member akfisherman's Avatar
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    Quote Originally Posted by AKBroncoII View Post
    I want more real boater experience. I've already been in direct contact with bennett. It does me no good for a guy to be sitting at a computer answering emails with no real world experience of boats or their own product other than videos. I want real world feedback and experiences.
    I posted earlier that I put a set of Bennett sport tabs on my boat and I was very happy with them. I also provided you with their website so you could easily take a look at the design and technical information. If you want to know how the tabs will work on your boat then you need to find someone that has put them on you particular boat. The handling and performance I get will be considerably different than yours. I found that bennentt provided me with a very good well made product that installed easily and works like I had expected for my application.


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  15. #15

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    Quote Originally Posted by akfisherman View Post
    I posted earlier that I put a set of Bennett sport tabs on my boat and I was very happy with them. I also provided you with their website so you could easily take a look at the design and technical information. If you want to know how the tabs will work on your boat then you need to find someone that has put them on you particular boat. The handling and performance I get will be considerably different than yours. I found that bennentt provided me with a very good well made product that installed easily and works like I had expected for my application.


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    I realize you have me info. I understand the design differences between the sport tab and standard tab. They make two different types of sport tabs. Which ones did you use? They make a dual cylinder tab and a single cylinder tab. Both are slightly different in design. What size tab did you end up going with?

    There is very little info on these boats as they've just begun to hit the private market used. They are not forthcoming with any information on these vessels as the majority of usage and info is proprietary. Just to get them to talk to the dealer here about engine mounting was almost impossible.

  16. #16
    Member akfisherman's Avatar
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    I have the m80 sport tabs. They are smaller and supposedly provide more lift. I have a 20' boat


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    Member Akgramps's Avatar
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    Just talking here from my computer... so it may not be good advice..... tabs are typically used to correct a issue or condition caused by a change in weight and balance or variable water condition, (sounds pretty good for something I just made up...eh)...

    If you are having porpoising issues assume you are light in front...? Hull condition, weight...? I assume you cannot correct with trimming the motor....? May seem like stupid question but you really didnt say other than porpoising issues and the boat you bought has no customer service...

    In any case, you could try some transom shims to see if that solves the issue,

    http://thmarine.com/cmc-transom-wedges-2-degree.html



    Anytime you can run w/o tabs I think you are better off, they are for correcting a temporary situation, and not necessarily a perm fix. If you have to run w/tabs all the time, it can create a potential hazard, particularly in a following sea... or some such condition like at...
    “Nothing worth doing is easy”
    TR

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    Quote Originally Posted by AKBroncoII View Post
    My bottom already extends out 5" from my transom. I believe that is why it flattens out at higher speeds.
    If this looks like what I think it looks like, bend it down slightly and see what it happens...
    “Nothing worth doing is easy”
    TR

  19. #19
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    I am leaning more to the side you are over trimmed more so than the need for trim tabs. "When over trimmed the bow might begin to rise and fall rhythmically, which is called porpoising. Extreme over trim can cause the propeller to lose its grip on the water, a situation called cavitation. "

    This was a excellent article http://yamahaoutboards.com/yamaha-ad...-and-trim-tabs You may find it as helpful and save you some money. I know trim tabs are expensive and if you can fix the problem without then great.

    Sweepint
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  20. #20

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    Quote Originally Posted by Akgramps View Post
    Just talking here from my computer... so it may not be good advice..... tabs are typically used to correct a issue or condition caused by a change in weight and balance or variable water condition, (sounds pretty good for something I just made up...eh)...

    If you are having porpoising issues assume you are light in front...? Hull condition, weight...? I assume you cannot correct with trimming the motor....? May seem like stupid question but you really didnt say other than porpoising issues and the boat you bought has no customer service...

    In any case, you could try some transom shims to see if that solves the issue,

    http://thmarine.com/cmc-transom-wedges-2-degree.html



    Anytime you can run w/o tabs I think you are better off, they are for correcting a temporary situation, and not necessarily a perm fix. If you have to run w/tabs all the time, it can create a potential hazard, particularly in a following sea... or some such condition like at...
    I appreciate the humor. Ahahaha. I am looking to force the bow down at lower speeds. It is definitely light in the front. The fuel tank butts up against the transom. At 1350lbs of engine on the transom and 125 gallons of fuel in the tank. It's 2000 lbs at the transom. This vessel is designed to run fast. At 40kts it lays down perfectly flat for the most part. I just don't want to do 40kts everywhere. Makes for a hefty fuel bill. I need slightly more lift out of the back.

    I Had considered doing exactly as you suggested with bending the tabs down that extend from the transom. Not sure how I would accomplish it as they are 20" long by 5" wide and 1/4" thick. If I was off just a tad I don't believe it would sit level under power. Trimmed all the way in, it still won't push the bow down. It could be caused by transome angle but even running shims, I'd just get more trim up and not in, which is what I would need to force the bow down.

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