can anyone help with boat handling problems

[Dave]

My boat is a 21' open bow, Im having problems when I get to the speeds of 75-80mph on GPS the boat wants to chine walk. Ive got tabs on the back and Ive tride every position but it still is not helping out. So I hope there is some one out there, that some info for me thank can REALLY HELP I know the boat will go faster but I cant get it there until I get it to handle thanks Dave

[Havasu Hangin']

My boat is a 21' open bow, Im having problems when I get to the speeds of 75-80mph on GPS the boat wants to chine walk. Ive got tabs on the back and Ive tride every position but it still is not helping out. So I hope there is some one out there, that some info for me thank can REALLY HELP I know the boat will go faster but I cant get it there until I get it to handle thanks Dave
Most boats won't let you drive through a chine walk. Keep the tabs level...and drop them down a couple inches when it starts to chine walk. It will push the nose down a little (and probably scrub some speed off)...but at least you'll be alive.

[Riverkid]

What are you driving?

[Dave]

it is a 91 legend (manufacture)Falco(model) but says eliminater on the side of the boat. It has a bravo 1 drive and a 555 BB Im running a 28pitch 4 blade SS prop and its turning 5100 rpm at 81mph on the gps.

[Havasu47]

more than likely you have too small of tabs. Are they Bennetts or something similar?
An 80 MPH boat requires a better and longer tab like K-Planes or Dana tabs. I know....... it is only a 21 footer, but at 80 the boat is fairly dry and the short tab is inefective. The longer the tab, the less "down" and the less speed you will scrub off keeping the boat from chine walking.

[jackpunx]

Also consider that hull could be maxed out at that speed. It may not be safe to get that boat above 80.
do you have hydro steering?

[Just Tool'n]

Do you have any type of beefed up steering?
Single or dual hyd steering?
At that speed you need them, safety first!
look into this first!

[bigkatboat]

Next time you run the boat fast, find out where the hull is riding in/out of the water. I think you are getting "off" of the center strakes. This lets the hull (all of the weight and torque) ride on the 'rounded, non- straked rear area' of the hull. Often a hull will have a 6"+ wide "pad bottom" to stop this, and you don't have a delta pad bottom. You can (glass the inside) and grind in a delta pad, or you can add smaller (1" wide) strakes behind the center strakes, go to within 30" of the transom. I like the strakes (idea) better, it gets more boat out of the water. The 'plates' will help but will add drag to the boat and never really correct the problem. Strakes "lift" and stop the 'rolling' of the torque reaction your prop/ motor combo is pushing with.

[Dave]

the trim tabs on the back measure 16 inches long and 12 inches wide I also have dual stering stabalizers made by sidewinder and single hydo steering.

[spectras only]

[b]Next time you run the boat fast, find out where the hull is riding in/out of the water. I think you are getting "off" of the center strakes. This lets the hull (all of the weight and torque) ride on the 'rounded, non- straked rear area' of the hull. Strakes "lift" and stop the 'rolling' of the torque reaction your prop/ motor combo is pushing with.
BKB is right . You probably have no strakes going all the way to the transom.
My boat has counter rotating props , yet chinewalks over 70 for the same reason [ inside strakes stop 10' forward the transom. I have a 12" wide V deltapad as well . My boat rides on its tail at WOT , and the K-planes do work well to stop walking ,only loosing a couple of miles in speed.Here's a shot going 65 .
http://www3.telus.net/spectrasonly/mirage%20in%20deep%20cove.jpg
http://www3.telus.net/spectrasonly/Img_0501.jpg
Also ,some boats reach their safe max speed limit at a certain speed. My boat seen max 84MPH with s/c stroker motors in the past , and it was a handful at that :idea: :D