What effect does motor height have on attitude (bow lift, porpoising, etc)?

[Fed]

Well done jimmbo you stopped his gobbledygook for three whole days, very impressive mate.

 

[jimmbo]

It is nothing to Gloat or be Proud about.

 

[Faztbullet]

In real boating world it doesn't matter at all the shape of the hardened water flow exiting right the middle rear hull,​

100% proof he has no idea of hull/motor correlations.

 

[Sea Rider]

It’s a pity that Jim Alabama has not reported what was asked so to enlighten the forum audience about at which lower leg height was his combo performing amazingly spot on as reported after raising the motor. Read that Fed a forum member has joined this conversation just to withstand Wisefuz’s posts trashing my posts while paying homage to this undisputed top notch guru of the entire prop section with whom have been mostly having repeated boating tech clashes.

Hey Jimbo, locate yourself, don’t put words on me, never stated that the water flow must run right in middle of both plates, you guys like for flow to skim right over or even under the Av plate. I like skimming right under the upper deflector plate. You have issues with that or you want me and any other new boaters who seeks information to go per your motor height parameters. If you guys are so darn experienced boaters owners of the holly grail of truth, tell the audience what’s the purpose of the small lip protruding ahead of the upper plate for, is it a cool ornament, some kind of step ladder to climb on board from behind, a device to open beer bottles when beaching ? There are many issues that you guys don’t know anything about and if knowing about you simply like to ignore them due to not being written cast on stone anywhere nor stated by word of mouth.

I don’t need to add any extra doel fin, smart tabs nor motor risers, jacks as I don’t have any issues shimming up or shaving any transom down for my particular and friends spot on boating, have an issue with that too ?

Will entirely agree that if those 4 posted motor height examples works spot on for Merc’s and Evi’s oldie motors, who am I to state otherwise. The issue with you guys is that you give a darn about at which lower leg height the hardened water flow passes by through the lower leg as you can correct any performance issue with trim along an expensive SS prop change. Hurrah!!!!

You don’t have the slight idea that over the last 50 years the lower leg’s plates height distances have evolved from very short ones to much longer ones and you guys are throwing both motors styles in same wide sack. Check...



As said before, if Old Timers likes boating following Carl Khafer’s and Ole Evinrude’s old motor height parameters to the letter keep doing so, will keep boating on my side with my own proven parameters which works spot on for me and my UK and Aussi boating mates. information which is not posted nowhere, happens that was discovered by myself and I’m just sharing this proven info here,. So bug off boaters running Jurassic motors, let new boaters running modern motors to experience for themselves.



Happy Boating

 

[jimmbo]

It doesn’t matter if there is 2”, 4”, or even 10 inches between the AV Plate and a Splash Shield/Deflector. The general Recommendation by Engine manufacturers is to run the AV Plate even with the hull bottom, and as speed goes up to mount the engine with the AV Plate at higher heights

 

[Texasmark]

Was over at Utube today and accidentally stumbled across a guy with a John Boat (with the Bimini top up no less), powered by a 40 hp Yammie tiller. He was showing off his jack plate. He had no PTT and in the 2 pictures the engine pitch didn't seem to have changed. He was running a SS prop with no details about it. He ran the camera across his GPS receiver to verify his readings.

Jack plate all the way down....sitting where it would normally be (but he had a few inches of setback with the jack plate...common to both tests however).......30 MPH.

Jacked the plate all the way up .......37 MPH.

He included side views on the trailer of Anti Vent plate vs hull bottom in both positions.

That right there is proof in the pudding for non believers about engine height vs this and that to answer the question of this thread.

Interesting video....might want to check it out.

 

[Texasmark]

Then why is it that what I said happens to ME with everything the same except engine height? The majority of what I blab about on here has happened to me over 50 years of boating....actually 78-15=63 years of boating having had a couple dozen over the years of many types to 19' and 125 hp. Being a retired Electromechanical engineer by profession, I made my living understanding why this affected that and changing X caused this change in Y and so on. So on my boats with PTT, dipping the nose of the AV plate in the new water a bit gives me better bow lift, as does the tail with the opposite effect.