Re: hydrofoil or trim tabs or both??
Hmm good sales pitch!
By "FIXED" I meant FIXED adjustment. (non-operator controlled)
AND "Smart" Tabs don't cause drag and affect fuel consumption in a negative way?
ALL tabs will produce drag if touching the water at any speed.
And drag will increase as the square of velocity...... which means FIXED pressure tabs (fixed gas pressure is equivalent to fixed spring pressure) will also cause drag at any speed. The gas cyls they use with the tabs produce damping in the movement of the tabs but still apply a down pressure at all times keeping the tabs in contact with the water.
I will not get into an discussion of the benefits of fixed (pressure) tabs vs fully adjustable tabs. But no amount of marketing hype will convince me that that the laws of Physics (and Hydrodynamics) , can be circumvented.
ALL TABS produce drag if they touch the water. The drag is less or (IN-) significant at low speed where the "Smart" Tabs effectively help produce lift.
But because they cannot adjusted out of the water at higher speeds, the drag WILL reduce top speed and increase fuel consumption at higher speeds...... It's an acceptable engineering tradeoff, but a tradeoff nonetheless.
You make what sounds like a reasonable point that all tabs cause drag. Well of coarse they do, when they are deployed, but the lift and better operating attitude of the boat is the reason that drag is exceptable. When the boat gets on a plane faster at less rpms it is more efficient to a certain speed. When a boats stern is raised and put in a better forward thrust position, the drag from the tabs is exceptable to a certain speed.
Now, as far as top speed gain, I promise you they work for speed improvement as well. The reason they do work, is because the actuators are valved and relaxed so when on a plane they have just enough pressure left on them to obtain stability improvements from side to side and bow to stern movement.. Like you said, there is a trade off! The stability improvements is what causes the boat to improve speed. Yes, they are still going to deployed up and down when going over uneven waves, which by the way is all the time. But while on a plane the smart tabs drag is minimized with the smart tabs and the trade off is you get better performance in other areas that will in turn increase top end speed. If the boat runs smoother and more stabile across the water, it will go faster than one that doesn't.
The gas valves do not act like springs, springs load up and actually would cause more and more drag, the more they were compressed. These gas actuators are valved and sized to the boat so as you get to a planing speed and the gas actuator is compressed, the relief valve releases pressure as to not drag significantly. The actually operate the opposite of a spring because the do not load up creating more resistance. That is what makes the smart tab smart.
I'm not speaking from there marketing, I'm speaking of what I have experienced from them in the last two years of running them. I can also say, I get alot better fuel efficientcy with the tabs, the fuel savings alone in the last two years have surely paid for the tabs themselves. They do everything that they claim and I have found that most people don't believe it until they have them installed and try them.
I'm not hear to convince you, but I will speak to my experience and knowledge of the product and what it offers so others can make there judgement of what they want to buy to improve there boats performance and efficientcy.
The main reason I purchased them, is because I liked the idea of the tabs self adjusting all the time to the changing conditions, instead of me having to self adjust the helm controls all the time up and down for the changing conditions. I had no idea really that I would see the improvements I have.
Helm controlled tabs have there place, they out perform smart tabs in some areas, but I have said it before, I think smart tabs outperform helm controlled tabs in more areas for smaller boats 26 ft and under...
So I don't get hammered, I am not saying smart tabs are better for all boats or better than helm controlled tabs period. They are simply just better for some boats,some sizes and some uses. .
