Jdeagro Some trim tab advice plz

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Iv'e gotten myself into a little project here, and it involve's some chine waik or some kind of stabilty issue.(left to right wobble) Trying to be short, new prop 4bl type has so much overall lift @ 54mph and above i experiance the above problem and am hoping the tabs will dampen this somewhat.Here's a pic of the boat and where i think shes ride's @ wot (thin red line)
Picture034-3.jpg


This boat is a 2800lb, 225hp I/O, the tabs i currnetly have are ST1290-60 8ft beam 20 degree v.The boat really doesnt need the lift out of the hole but it will be nice, what i am really looking for again is to stablize the wobble or chine walk

Picture034-1-2.jpg

Picture035-1.jpg
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: Jdeagro Some trim tab advice plz

Me thinks JD takes the weekend off Tail Gunner. Hang tight!
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

:'( Damm i got the itch tooo.... Ohh well the guy is so much on top of his game.............i guess a weekend or 2 is probably in order
 

rondi

Petty Officer 2nd Class
Joined
Oct 16, 2006
Messages
102
Re: Jdeagro Some trim tab advice plz

I'm guessing that John would rather you remount your trailer straps something like this and have the tabs mounted here.
trailerstraps.jpg
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

Thank you, that placement looks right to me also, however what i am trying to accomplish is stability @ high speed.............that thin red line is where she rides @ wot. Putting the tabs up that high im afraid might cause a drag or might not create enough stability it need's...........:} maybe some dimesion's would in order.

Picture034-1-3.jpg


The heavy black line is 8" above the keel and the red line is 4 1/2" off the keel, the beam is 8'
 

Jdeagro

iboats.com Partner
Joined
Jul 30, 2003
Messages
1,682
Re: Jdeagro Some trim tab advice plz

Sometimes I am on the site over the week end but I was not this week end.

Anyway, the further out board the tabs are set the better control over the side to side stability. You are correct, the boat is rideing high in the water when at speed and it has very little surface area to control the chine walking. I would choose a location where the Top part of the actuator (transom mounting bracket) is just inside of the extension bubles. This will put some of the plate under the bubles. The issue then is the tie downs but that should be easy to reposition.

Even at high speeds, the tabs will have enough water contact (splash, spray, and water) to correct the chinewalking. Placing the tabs too far inboard will reduce the leverage that they need to correct the problem. I am not saying that the inboard mounting wount work, as it may, but spreading them will work for sure. The first picture is close to what i would recommend, but push them out a bit more. Try to keep the transom bracket on the transom flat surface. Rotate the bracket so that the actuators can come off toward the inside of the boat. The end fittings will rotate.
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: Jdeagro Some trim tab advice plz

Edit: Never mind, John covered it.
 

rondi

Petty Officer 2nd Class
Joined
Oct 16, 2006
Messages
102
Re: Jdeagro Some trim tab advice plz

Tail Gunner: Please give us an update after you install and show how you repositioned the tie straps. (w / pics)
I too have this project sitting on the back-burner now, with a fresh box of smart tabs sitting on my bench in the garage.
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

d:) Thank's john and you to rondi will update tommorrow
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

Tail_Gunner said:
d:) Thank's john and you to rondi will update tommorrow


8) simple enough
0318-0.jpg


One bolted on each side of the bullet ...........mounted to the trailer that is......:}
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

rondi said:
Tail Gunner: Please give us an update after you install and show how you repositioned the tie straps. (w / pics)
I too have this project sitting on the back-burner now, with a fresh box of smart tabs sitting on my bench in the garage.

Picture008-1.jpg


Picture009-1.jpg


That's a 1/2 stainless eye bolt, i might go to two but for not im satisfied.
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: Jdeagro Some trim tab advice plz

Looks like you could have left your tie down straps where they were TG? They would have missed the trim tab top cylinder mounts.
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

Boomyal said:
Looks like you could have left your tie down straps where they were TG? They would have missed the trim tab top cylinder mounts.

:love: Good eye, your probalby right. Let me ty'em up and see what happen's, yet though i do like the central tie down idea, there's a certain charm to it...... aka all the tension is placed on the keel leaving the hull to float on the bunks........ bahh who know's
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

Tail_Gunner said:
Boomyal said:
Looks like you could have left your tie down straps where they were TG? They would have missed the trim tab top cylinder mounts.

:love: Good eye, your probalby right. Let me ty'em up and see what happen's, yet though i do like the central tie down idea, there's a certain charm to it...... aka all the tension is placed on the keel leaving the hull to float on the bunks........ bahh who know's

Bye the way im sure you noticed how tight i placed those tab's and if you look closer i think you will find that hull and your new lady are very similar. We need to compare there very close from the pics ive seen
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: Jdeagro Some trim tab advice plz

You talkin about this lady TG? I should take a picture from straight on. It does have more deadrise than my Gulfstream. This is the hull I should have tried to stick a stroked 302 to 331 cid into. Then I would probably had the same kind of handling problem you did. However this old 302 runs so sweet I'd hate to mess with it.

DSCF0229.jpg
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Jdeagro Some trim tab advice plz

Picture008-1.jpg


DSCF0229.jpg


Yes take those bubble's off and some of the top mold maybe a a bit more swoopy and the hull's look very much the same i've seen a pic of your bow and it look almost identical,rake of the v chine and strakes, does your keel run a straight line from the bow to the stern no dip's or curve's?
 

Boomyal

Supreme Mariner
Joined
Aug 16, 2003
Messages
12,072
Re: Jdeagro Some trim tab advice plz

Here's a front view TG. The keel runs straight to the transom once it reaches the bottom of the bow line.

DSCF0388.jpg
 
Top