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Thread: trim tabs

  1. #1

    trim tabs

    hi all
    has any body used self levelling trim tabs and do they work like take the lead out when traveling with side on wind

  2. #2

    Re: trim tabs

    Sorry can’t help but I do know there a stack of info on this site about trim tabs. Try the search, there is plenty


    Sent from my iPad using Ausfish forums

  3. #3

    Re: trim tabs

    Not too sure the auto ones are quite as good as manual ones, and yes, trim tabs will help keep your boat level when travelling side on, don't you just love it when you get smashed down on one side......

  4. #4

    Re: trim tabs

    I will be looking at auto trim tabs shortly too mostly just to stabalise the hull no matter where people stand inside the boat

    39 What brand are u looking at buying?

  5. #5

    Re: trim tabs

    I prefer manual. They are quick to adjust and also get them to sit the boat how you like

  6. #6
    Ausfish Platinum Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: trim tabs

    I use Bennet hydraulic, boat is going on 3 years old, no problems. I didn't get the position indicator fitted, which is a mistake in retrospect, as you have to remember what you have done. Only way around it it to hold down the switches to make sure they are both all the way up. They are touted as an absolute must on all larger hulls--they certainly have their uses. When I first got them, I was using them all the time, but came to realise that this hull just didn't need them down at all most of the time. A well designed hull , evenly loaded, doesn't need them down at all, motor trim will do it. I would never go automatic, you don't need a system like that stuffing around with trim running fast downwind, thank you.
    You must remember that using these things almost always costs you fuel, and are used to counter either 1) poor hull design b) poor weight placement, including fitting motors which are too heavy , or 3) lean into a cross wind. The last one is a definite plus. As for the others, well, the weight placement , if it isn't down to the motor, can sometimes be rectified. As in, " get yer fat **rse off the transom and stand further forward " My only use for them nowadays, apart from the crosswind thing, would be to get the boat planing at under 13knots in extreme conditions, it will do that with tabs down and motor trim neutral. I'll go weeks, months, without lowering them. I have a hull which is an absolute delight to drive in all conditions, predictable and safe, responsive to motor trim, I just can't seem to find its limits. But not all are so lucky.
    To sum it up, get Manual, and position indicators with them. If you are new to boating, you aren't learning anything by automating everything.

  7. #7
    Ausfish Addict disorderly's Avatar
    Join Date
    Sep 2006
    Location
    In the Jungle/Mission Beach Hinterland

    Re: trim tabs

    I think those trim tabs are just spring loaded and there is no manual control at all...but might be fine for a smaller tinny..

    I'm just fitting some at the moment but I have had them for 18 months and wanted to get to know how my hull handles in various seas before fitting them...

    https://www.jpwmarine.com.au/bennett...ystem-jpw16047


    Being a 24 degree deadrise hull it is sensitive to weight placement and does lean into the wind..

    level trim till now can be achieved by correct weight distribution of eskies, gear and passengers so I will always take that into consideration but it would be nice not to have to bother about it too much particularly if running into a 45 degree beam sea where I dont want it slapping into the waves or when people decide to move around on deck...

    I'm fitting these hydraulic tabs with the auto function.they can be used manually but can be switiched to auto also..I'm interested to see how that goes...we also got the sports tabs which are a batwing style to increase lift which might be handy in those challenging conditions ..

    What are you concerns with the auto ones Ranmar..?..have you heard of issues with them exacerbating broaching ..?..also when using yours is there a noticeable difference in fuel use..?

    cheers Scott

  8. #8
    Ausfish Platinum Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: trim tabs

    Well, if they decide to trim down for whatever reason as you surf down the face of a big one, best case would be bow steer, which is only a prelude to broaching. I'd rather have full control, they should always be fully up running downwind/downsea. The auto tabs " shouldn't" do that, but.... As for fuel consumption, increased is a given as they are adding drag, thats how they are forcing the bow down. I've watched my litres per nm average both ways, you are always using more with significant tab down. The only exception to this is probably a badly overloaded/propped boat, which simply won't get onto the plane . In this case the tabs may make the difference, get you planing. The lean into the wind thing isn't limited to deep vees, anything with significant windage will do it. It had me puzzled as to why hulls do it, until it dawned one day. I was travelling across a strong offshore close to the beach, coming from port, 30 knots of wind and no sea. Quite a lean on ( in my previous boat, no tabs) . Then I hit a hole in the wind and veered very sharply port before I corrected. Then it dawned on me--the lean is caused by steering correction unconsciously applied into the wind to counteract the wind force on the superstructure. Take the wind away suddenly, you'll steer hard in the direction the wind was coming from. So tab down on one side will compensate for the lean.

  9. #9

    Re: trim tabs

    Quote Originally Posted by ranmar850 View Post
    Well, if they decide to trim down for whatever reason as you surf down the face of a big one, best case would be bow steer, which is only a prelude to broaching. I'd rather have full control, they should always be fully up running downwind/downsea. The auto tabs " shouldn't" do that, but.... As for fuel consumption, increased is a given as they are adding drag, thats how they are forcing the bow down. I've watched my litres per nm average both ways, you are always using more with significant tab down. The only exception to this is probably a badly overloaded/propped boat, which simply won't get onto the plane . In this case the tabs may make the difference, get you planing. The lean into the wind thing isn't limited to deep vees, anything with significant windage will do it. It had me puzzled as to why hulls do it, until it dawned one day. I was travelling across a strong offshore close to the beach, coming from port, 30 knots of wind and no sea. Quite a lean on ( in my previous boat, no tabs) . Then I hit a hole in the wind and veered very sharply port before I corrected. Then it dawned on me--the lean is caused by steering correction unconsciously applied into the wind to counteract the wind force on the superstructure. Take the wind away suddenly, you'll steer hard in the direction the wind was coming from. So tab down on one side will compensate for the lean.
    Agree with manual adjustment of tabs, and yes, definitely go for indicator switches. The lean is caused by the wind which creates a low pressure just like an aeroplane wing. The wind drops off the pressure equalized and yes you do apply additional force to try and compensate. I would not like to think of crossing a bar with following seas and not knowing if my trim tabs just might deploy ar the wrong time.

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