Someone told me trip tabs help with fuel economy? I am guesing it would possibley help get the cav plate siting right with less drag if the motor was a touch to low.
Can anyone confirm any changes in fuel economy after using trim tabs.
I have spotted some Wireless ones that would be just great
Peter Webster claims the Volvo ones cost him a knot in top speed, (due to extra drag) on one of his F&B boat builds so thats most probably not a help with economy either.
Don't know if my flat plated Lencos are better or worse economy wise, I suspect better; as they, even when fully up, do lift the bum of my boat as evidenced by less spray being thrown about.
Based on the bum lift then, the cav plates on mine are higher too which is good.
Who makes wireless trim tabs?
Cheers
Chimo
What could go wrong.......................
2 - well many sides to this and depends on a lot of factors including style of trim tabs.
Trim tabs can add lift to the rear of the hull similar to a hull extension and give you the ability to have a lower plane speed . This lower plane speed would be more effecient than pushinga big bow wave just off the plane without them.
Top speed may be better or worse depending on style of trim tabs and the conditions you are measuring them in and if the prop is designed to work higher up if the tabs give the stern lift.
Where they are fited on the hull make a huge difference to how effecient and how much lift / hull extension they give.
The volvo vertical slide ones should be used on boats where there is no great benefit or a reason not to ( like a net boat where you don't want any obstructions to catch on) or the boat rides perfectly with a range of loads and they are used for lateral trim and attitude alone. The volvo ones work by disturbing the waterflow and would cause some extra resistance but by the same token if they place the correct amount of boats waterline length and planing surfaces they could be more effecient. Outright top end speed WOT as usual is a poor comparison for just about everything on boats except if you have a drag boat.
With P Websters test if the boat was 100% set up right , tabs would have been 100 % retracted and not affecting anything but when you have tabs you always want to change the boats attitude for ride etc. Could go either way for fuel ecconomy.
You can get more fuel effeciency with the right trim tabs at different speeds , better holeshot, better attitude in a lot of conditions so you are not on and off the throttle, better load carrying, not having to correct for wing so you track straighter etc etc. These may add up to either a better ride, more controlable , more enjoyable set and forget journey and or a bit less fuel.
I don't think there will be a 100% solution to more effeciency in everyones set up at every speed.
Just select your tabs for the purpose you need them and learn to use em properly along with the motors trim.
Specific to your boat if it is the one pictured you already have 2 donks - bloody great big trim tabs and the toe in and toe out of these motors and seperate trim of each has a similar affect. Again it all comes down to the props, wave and wind direction and loading of the boat and how sensitive it is to weighta nd trim. Before trim tabs we knew when going home we would load a bit more weight to one side with ice and gear - the old keep it simple . yes it was a compromise but a cheap easy one
http://www.lectrotab.com/products/wireless-control.phpOriginally Posted by Chimo
from lecrotab -
Improved Fuel Efficiency and Faster Speeds
Most importantly, the trim tabs may be adjusted to optimize speed and fuel efficiency. Typically, the bow rides high causing the stern to drag in the water at cruising or lower speeds. A boat owner will attempt to correct this problem by trimming his outdrive down to bring the bow down. This adjustment is extremely inefficient and reduces boat speed and increases fuel consumption, because trimming of the outdrive pushes water down to allow the transom to rise and bow to lower. In this scenario, the outdrive is not only propelling the boat forward but it is also pushing the bow down. The most efficient way to operate the boat is to adjust the tabs to maximize boat speed and level. The outdrive may then be adjusted so the prop shaft is parallel to the water to maximize the thrust to push the boat forward.
Kool, someone (Nowornever?) should get a set and try them out and tell us how they are.
What could go wrong.......................
Chimo,Peter Webster claims the Volvo ones cost him a knot in top speed, (due to extra drag) on one of his F&B boat builds so thats most probably not a help with economy either
Don't know if my flat plated Lencos are better or worse economy wise, I suspect better; as they, even when fully up, do lift the bum of my boat as evidenced by less spray being thrown about.
Based on the bum lift then, the cav plates on mine are higher too which is good.
Who makes wireless trim tabs?
Cheers
Chimo
If they lift the bum then they would be placing some sort of effort into the water = drag of some sort
I beleive the QL's will fully retract leaving no resistance in the water.
Any trim tab is really just like a hand brake its how you use the brake to better the ride which is the key. I use my tabs so I can run comfortably at an economical speed, without tabs I would need to run slower at a less economical speed. (the deckies luv em too)
Garry
Retired Honda Master Tech
I wouldn't believe "someone" all the time. To me the only way they can help economy is in the upright postition on the normal plate type tabs. They are effectively increasing your planing surface. As soon as you apply a bit of tab you are increasing drag so decreasing economy. In the real world, maybe what he was getting at is like what Garry said above, you can maintain a good slow plane without being on and off the throttle all the time so that is where you make it up. Same for foils. They ad drag but if they help you stay on clean plane for a lower throttle setting they are good when the chips are down.
Hey
I had the QL tabs on the 19C with the 200 Opti that had smartcraft gauges, as soon as they were adjusted (down) I would note that the economy L/KM increased by about 1 L/KM, that's if they were only slightly adjusted, more so in submarine mode.
Needless to say the boat was far better with them as opposed to without, but it came at a price.
Optimum economy was achieved with no tabs and motor trimmed out to just before cavitation occured.
Still, better with tabs than being without on any deep V boat from about 17' IMO, basically reinforcing what SP and Smithy have said.
Cheers
VS
Hi Gary
Yep I agree tabs when down do create some force on the water body as it flows past. More so the lower they are positioned.
Given that the affect that I referred to ie "bum lift" (technical term) occurs when the tabs are fully up is it not possible that one is gaining a result from lengthening the hull as the tab is parallel to the hull bottom and can also be angled slightly above that too. The tab hinge was located by Seafarer so that the base of the tab plate is approx 3mm above the hull line so drag per say would be minimal at level or above level setting. Even in the "Up" position the Lencos make the Vag a better boat and in side winds or cross seas ditto as the hull works as it should.
The Volvo QLs that Peter Webster reported on in his F & B Mag story did lower the top speed of the boat reported by a kn and as you indicate that was probably happening when they were extended. I or others would need to find the story in the mag which is also do-able.
The point in this discussion re tabs is that Qls work as tabs when extended but more than likely add nothing to potentially lift the cav plate or improve economy unless extended and working as tabs which was the intent of Nowornever's question. (ref post 1). There is some impact (lift) from flat plated tabs like Lencos even when up which again attempts to address Nowornever's question.
As you say the use of tabs makes good boats better and does allow more economical speeds in greater comfort so we can agree they are worthwhile.
Cheers
Chimo
What could go wrong.......................
Chimo,
All the numbers have been done and the QL's create as much lift and maybe more than as any tab on the market however they have proven to bea thorn when fitted to boats which live in the brinny (they seize up from growth real bad)
Garry
Retired Honda Master Tech
The QLs are also no good if the boat is in the sand and or gravel all the time too like Brooksys electrofishing punt.
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