Motor height vs. permatrim

[serpa4]

Finally installed my permatrim on my Venture 26 with 200hp Suzuki.
Didn't realize any difference. MPG seemed down a tad.
On my Suzuki, there are two sets of horizontal fins. The lower on is obvious the anti-ventilation plate. About 2.5 inches above it there is a 2nd smaller rib, but it still protrudes about 1.5 inches and is fairly flat.
The 2nd higher on is about where my engine is in the water at 25mph.

Is my motor too low? If the anti-ventilation plate is riding the surface of the water, isn't the propeller about to come out of the water at the slightest wave, bump? Cant props suck in air from the surface also if its too close.

If it doesn't do much in that I don't notice it, then it might as well come off and get my mpg back. I have trim tabs also.

My searching on the internet always turns up pictures of deep V boats and their anti-V plates are like 1/3 way down the transom V that is in the water. I.e. if they draft 18" water, then the plate is about 9" below the water line when sitting level. Haven't seen (yet) a video of a boat on plane.

[thataway]

You want the anti ventilation plat just under the surface of the water. Usually this is about "level" with the bottom of. the C Dory/Venture. The Permatrim should be just on the surface of the water.

It sounds as if your motor is too low==maybe even two holes too low--but go up one.

What is your WOT RPM, and Boat speed? You will get very little decrease in speed or MPG--but it can be measured. The permatrim allow you to get your bow way down when going into chop, and that gives a much better ride. Trim the motor up for going down waves/wind. You will probably plane at a slightly lower speed.

[serpa4]

[thataway]

The first question we often ask is: "What is your Wide open throttle RPM and speed." implied with this is "is your boat trimmed or the best possible speed for the condition." "Are you lugging the engine, or not achieving the best speed for the RPM"

The ant-ventilation plate is the first plate one above the prop, and contains the trim tab. This should run just under the surface of the water, and the Permatirm should be mounted right above this on just on the surface of the water.

The anti-ventilation plate should be from 1/2" to level with the bottom of the boat. Depending on type of hull--the deep v (in the 20's dead rise) would be the deepest motor. Since our C Dorys/Ventures, have extremely low dead rise, the anti-ventilation would be right at the same level. I have tried my boats to have the Permatrim right at the surface of the water--no cavitation-depending on the hull type. For example , my other boat is an 18' Center console Catamaran. It has a skeg like projection I the tunnel, to help to direct the flow of the water coming out between the hulls. Single engine cats are notorious for blowing out--because of this skeg like appendage)-a properly set up Caracal Cat has this minimized. Going down wind / waves, I will occasionally have some cavitation, For this reason, ideally I should have a remotely operated jack plat installed. (I don't have one.)

[serpa4]

Measurements say my anticavitation plate is about 1 or 1.5 inches higher than the bottom of the hull. Both are level with a bubble gauge.

[NORO LIM]

Serpa4, just to make sure everybody is on the same page here. When you are assessing the depth of the Pematrim below the surface of the water, are you talking about while the boat is on plane? That is definitely what you need to check. The Permatrim should be right at the surface (maybe a slight film of water running over it) when the boat is on plane. Obviously, it takes at least two people to check this - unless you are completely reckless and willing to leave the helm while the boat is planing!

[serpa4]

[NORO LIM]

[thataway]