Boat lists,porposes while on plane.

alldodge

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Personally I think the jack plate may be causing most of your issue. Most folks that use them are the bass boats which are able to lift the hole boat out of the water except for maybe about a foot square. The jack plate should be able to position the cav plate directly even with the bottom of the keel to no more then 1 inch above. Here is a good read
http://media.channelblade.com/boat_...s/dts/dealerlibraries/8441/copetipstricks.pdf
 

juicegoose

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Down here in Texas & Louisiana most bass boats don't have them and most bay boats do. Hahah go figure. I will have a chance new years weekend to take the pictures your asking. I'll take a picture of the cav plate with the motor all the way down and all the way up. Also i'll take the picture from the top of the tunnel. That Is where the flow of water is coming from for the prop.
Anything else recommended I try out?
 

alldodge

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No that should be good for now, others may come in and provide their thoughts. I guess if you get into shallow water a jack plate would be real good to have to pull the engine up high.
 

juicegoose

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I don't fish in shallow water but it has helped while getting into my boat slip during a winter north wind. The canal can get shallow and I'll generally jack the engine all the way up to keep the skeg out the mud. While running around I'll generally keep the plate at 3
 

Tail_Gunner

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Here's is what I would do raise your jack plate until your prop tip is inline with your hull bottom. It's as simple testing thing's from there...it may just work fine right there or you may have to lower your drive leg one inch at a time until you achieve the proper balance..I have little or no experience with set back's it's to bad Dhadley ...Walleyehed or Texas Mark don't chime in here..Opp's I believe this is well within Jestor's wheel house.
 

Bondo

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Down here in Texas & Louisiana most bass boats don't have them and most bay boats do. Hahah go figure. I will have a chance new years weekend to take the pictures your asking. I'll take a picture of the cav plate with the motor all the way down and all the way up. Also i'll take the picture from the top of the tunnel. That Is where the flow of water is coming from for the prop.
Anything else recommended I try out?

Ayuh,.... Take a picture of the cav-plate with the motor at neutral trim, which may, or may not be all the way down,....

While yer down there, bring a 6' straight edge with ya, 'n check the last 4' of water surface for straightness,...
Ya could have a hook, or a rocker goin' on,....
 

Tail_Gunner

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Ayuh,.... Take a picture of the cav-plate with the motor at neutral trim, which may, or may not be all the way down,....

While yer down there, bring a 6' straight edge with ya, 'n check the last 4' of water surface for straightness,...
Ya could have a hook, or a rocker goin' on,....

I suspect that drive is running so deep he may have bent a hook in it recently....:D


With that engine boat combo and 35 mph that drive is running quite deep in that pic the bow is deep in.

fetch
 
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juicegoose

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The boat has done this since I've bought it. When I test drove it the original owner wasn't comfortable letting someone else drive it. I didn't think anything of it as I would kinda feel the same way. The original prop on the boat was a powertech 3 blade 21p. It kept blowing out and when I brought it in for service the guy showed me what the diameter should have been. Literally an 1" of prop was gone. Even with that prop and before I got trim tabs the boat listed slightly to port and would porpose. I could 50mph out of her wide open though at 5500 rpm.

Tail gunner the V on that hull actually stops right at the center console and then the pocket tunnel starts a reverse angle back up to the keep.

Bondo.
When you say motor in neutral trim do you mind explaining?

Thanks guys for all your help I really appreciate it. I've loved the fishability of the boat but this porposing is annoying.
 

alldodge

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You have a tunnel but the neutral trim means to have the drive even with the bottom of the keel
AntiventilationPlateStraightEdge-2.jpg

Now with you having a tunnel the keel is the top of the tunnel
 

juicegoose

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Okay Guys I'm heading out this weekend to my camphouse to do some testing I had a couple questions.
What sort of testing should I do while in the water? My plan was the following
Before launching the boat
-Check planning surface for any hooks or rockers.
-Take pictures of cav plate in neutral trim in relation to top of tunnel and at all levels on my jackplate.
- Run the motor and achieve WOT rpms and speed
-Test time to plane and rpm to push over onto plane
Question on that step. Should I go full power or typical power which is about 3/4 to test the time to plane?
-Unhook trim tabs and store up to make sure they aren't the cause of the listing.
-Test various points at which the boat begins to porpoise. My method was to put the boat in the full down position on jackplate tuck the motor, get to planning and then count how many clicks on the trim until porposing is noticed. Raise the jackplate 1" and repeat. After which taking picture of the various points to show you guys which seemed to work best.

Anything I'm missing? Is there anything in particular I need to be keeping track of or trying out? I don't have the boat close by so testing is a bear. hehehe
 

alldodge

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I think you have it, and your pics and finding should help. Thought about this last night and porpoising starts when the drive is trimmed up to much. The tunnel should only cause the prop cavitation. Look forward to seeing results
 

juicegoose

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Dodge I agree that trimming up to much will cause the porposing but shouldn't I have the ability to trim the motor out enough to free up the steering some? As it stands right now If I leave the motor tucked in without adding trim tabs the boat is very hard to turn one direction(can't remember of hand which) and I've noticed it also tends to drift that same direction. If I'm traveling in slick water and trimmed out to a steady ride and I loosen my grip on the wheel the nose will begin to pull slightly to the right. Is that normal for a torquie prop like the rev4?
 

alldodge

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The prop is turning to the right so if you release the steering it will go to the right, harder to steer to the left. Doesn't matter what kind of prop, they all will give similar effect but there are some differences. You do have power steering assist on the motor right? I would like to see a pic of the boat at WOT to see how much hull is in the water.
 

juicegoose

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I have sea star hydraulic steering. I will get a picture of the boat at WOT too this weekend
 

alldodge

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I have sea star hydraulic steering. I will get a picture of the boat at WOT too this weekend

With full hydraulic steering there should be no issue with wondering or hard to steer. This could be another problem, which model is it?
 

juicegoose

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Not sure which model but it is your typical sea star hydraulic steering unit with a helm reservoir under the dash that the wheel goes to and a hydraulic cylinder mounted to the engine for steering
 

Tail_Gunner

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I took some time and read a bit on tunnel hull's it seems it's a balance issue 99% of the time. From what ive read one would set up the boat aka.. fuel.. passenger's equipment etc etc the way you intend to run most of the time. From there I would raise the motor so the blade tip is one inch Above the hull bottom this is not a deep v...and see how that works..Does it.... launch well....how's the.... mid range and a...WOT....run. You may find your self chasing drive height quite a bit with varying result's....you may have to even raise the engine higher than one inch. or lower than three inch's you will need to experiment.

What you trying to do is balance thrust so the boat ride's on it's outside sponson's in a tame manner...Leave the tabs on and pay close attention to the heat one can raise the engine high enough that it cannot pickup water and will over heat. One last note....get the best launch midrange balance you can....when you go to WOT be aware that aerodynamics...(air lift) will come into play be alert and ready life jacket on....:faint2:
 
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Bondo

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I took some time and read a bit on tunnel hull's it seems it's a balance issue 99% of the time. From what ive read one would set up the boat aka.. fuel.. passenger's equipment etc etc the way you intend to run most of the time. From there I would raise the motor so the blade tip is one inch Above the hull bottom this is not a deep v...and see how that works..Does it.... launch well....how's the.... mid range and a...WOT....run. You may find your self chasing drive height quite a bit with varying result's....you may have to even raise the engine higher than one inch. or lower than three inch's you will need to experiment.

What you trying to do is balance thrust so the boat ride's on it's outside sponson's in a tame manner...Leave the tabs on and pay close attention to the heat one can raise the engine high enough that it cannot pickup water and will over heat. One last note....get the best launch midrange balance you can....when you go to WOT be aware that aerodynamics...(air lift) will come into play be alert and ready life jacket on....:faint2:

Ayuh,..... 'n is where lookin' for a hook, or rocker is the Most important,.....

In the tunnel will be less important, or not at all important, though a straight runnin' surface is always Best,....

I wonder whether checkin' to see if the sponcon's are true to each other might be considered,..??
I'd think a toe-in, or toe-out might make a squirrelly hull,...
 
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juicegoose

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I think the bottom line is that the 200 is to much engine for the boat. Even Nautic Star admitted that the tunnel version with 200 had issues with porposing. What I have to do is find the best way to run the boat
 
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