Ventilation Plate Measurement

[JamesB]

Just read another post on mounting height and I am starting to wonder whether my motor is mounted correctly.   My ventilation plate is approx. 0.5" above the bottom of the hull.  At this height I am not seeing the entire ventilation plate out of the water and there is a lot of splash coming from the ventilation plates as it is hitting the water.   I could not call Defiance today to verify because they are closed.  I called another dealer and the guy on there was a complete moron.   He supposedly works in their service department but was very incompetent when I asked him basic questions.   My question is, if I raise my motor to the next hole, I will now be about 1.25" above the keel line in relation to the ventilation plate.   Can I ask owners of 17 and 19s to tell me how high above the keel line is your ventilation plate when your boat is on the trailer and trimmed out so that it's level with the keel line? 

[Fisherdv]

Are you seeing the plate at all while on plane? Should be just visible above the water. If you can see it, your weight shift as you move back to the helm may offset it. From your measurements that sounds about right. Some turbulence/spray is to be expected especially if you have trim tabs or transducers close to the motor. If you mount the motor too high, your prop will blow out trying to get on plane and in sharp turns. Are you having any performance issues currently, or just concerned about the spray?

Calling boat dealers/service department and asking for advice is most of the time useless. The will gladly take a look if you pay them though.

[JamesB]

concerned about the drag and loss in fuel economy due to the plate dragging in the water.  I can only see a small portion of the plate.  Can you see your entire ventilation plate skimming on top of the water?  If your boat is accessible, could you do me a favor and measure the distance from the keel line to the ventilation plate?  Or if anyone else has a bit of free time and can provide measurement that would be appreciated.  I know our boats and motors will be different but there's more similarities with all arimas than there are differences... butt heavy, sponsons, hull design, etc..  thanks

[Fisherdv]

I'm not at home to measure, but while I'm on plane I can see the ventilation plate just above the water.

A heavy load in the rear may also effect how much plate you are seeing. Full tank of fuel vs half full??? Extra batteries etc.

[Omega3]

The bottom of my ventilation plate is 1.25 inches higher than the bottom of the boat.No excessive spray or drag from motor or trim tabs.I have never really looked at the vent plate while running because I never felt the need.My motor is mounted in 3rd hole from the top.Pretty sure the guy that mounted my motor knows what he is doing,they have been selling Arimas for 30 years and used to build the teak hardtop structures.

[JamesB]

thanks FisherDV....

Omega, thanks for the info.  I have more confidence now that raising it would help me out since I have the same boat as yours and after raising it I will be at about the same height at 1.25" like yours.  Do you ever have any blowouts while cornering or have issues with porpoising?  I assume not since you said you have been happy with the setup.  thanks

[Omega3]

Any porpoiseing the trim tabs take care of with slight adjustments but it is minimal.I have never noticed blow out on corners but the only time I crank the wheel that hard at speed is to avoid hitting some sort of flotsam in the water.Arimas aren't jet boats meant for tight skinny rivers with tight bends.