Black Hawk top end issues

[Indyblackhawk]

We installed 285 K-Plane plates about 2 weeks ago. Running with 29p props right now. We put the plates on so that the indention is facing towards the outdrive, is this correct? When traveling at 65+ and continuing to lift the tabs all the way up the boat gets real side-to side- bouncy. Very scarry at 70+ and damn near impossible to get to 80 even with 500+HP. Any suggestions?

[Ed Donnelly]

The indentations face the drive,to give the drive more of a turning radius...Ed

[Blewbyu]

You should be putting the planes DOWN if the boat starts to chinewalk.....

[GEOO]

My Thoughts:
1)If your drive is trimmed to far in at high speeds, you could be getting bow steer. Make sure you have the drive trimmed up correctly.
2)You could try leaving the tabs down just a little to stop the rocking and not create to much drag.
3)Or give a light, quick shake of the steering wheel to stop or counter the rocking. Some times this will settle the boat and you can drive though it.

[Cuda]

I've found my Kaama drives are VERY sensitive to tabs. When I bought the boat, the previous owner told me to drop the tabs when planing off, then lift them once I got up. The boat would want to shoot off to the right or left while raising the tabs. I got so gun shy about raising the tabs that I once ran the first leg of a poker run with the boat heeled way over to one side because I was afraid to raise the tabs with all the boats around us. Since then, I now lower the drive way down, and leave the tabs up, or just a touch down on one side to keep the boat level. Now I RARELY touch the tabs. I found the higher the tabs are, the less sensitive to tabs it is. I think with not as much rudder surface in the water, the boat wants to turn with the tabs acting as the rudder force, and naturally, the less tab in the water, the less rudder force they are exerting.

Did that explanation make any sense?

[blackhawk]

Indy, is it chine walking AS you are raising the tabs or AFTER they are already up? I have 280 planes on mine and it will chine walk in dead calm water if I have the tabs down too far. In other words, the boat is bouncing back and forth between the tabs, not the hull. So, if I raise the tabs up it goes away. I know it sounds backwards but it works.

[Indyblackhawk]

It just gets scary when the bow is so high out of the water with tabs all the way up, feels very unsafe. Ive had a close call earlier this summer and now realize the potential dangerousness of this size of boat at such high speeds

[blackhawk]

Indy, I definitely know what you mean! I only run the tabs all the way up in calm water or water with good rhythm(is that how you spell that?).

Mine only walks in dead calm water dragging the tabs. In sloppy water I always drag a little tab to keep the bow down a little and it never walks on me. Is yours walking in all water conditions?

[Indyblackhawk]

Im going to be making alot more speed runs now that fall is here and its not so busy. Hopfully I will be able to better tell when it gets unstable. Over the summer its too busy/ rough in the day to run anywhere over upper 60's. If I can get to 80 with the 29's then ill switch up to the 31's to see what I get. Early spring with the short K-Planes and 29p's I hit 82 on GPS

[blackhawk]

You will like the longer planes in the slop. Made a big difference on my boat. Are you running external steering? If not, one thing you definitely want to check is the gimbal ring for wear/slop. Blackhawks can wear them out quickly without external steering.

I see in your first post you stated you had 500+ hp. Do you have the stock motor with upgrades or a different motor?

[Indyblackhawk]

yes it has Marine Machine External Steering but only one ram, looking to add the second over the winter. Boat has reprogramed ECM, Gil Headers, Gil stainless exhaust, merlin heads, 1.7 rollar rocker.... looking to add new intake setup and an aftermarket fuel regulator this winter... also would like to add an outdrive shower

[blackhawk]

Indy, I assume you have a 1.5 ratio drive? What rpm are you turning at 82 mph?

When you put on a drive shower use the innovative marine shower. Awesome piece and in my opinion the only one that will flow sufficient water for the blackhawk.

http://www.innovativemarine.net/SeaPump.html

As far as the walking I think you just need to get used to the tabs. It took me a little while to get used to them. Do you bring the tabs up then trim the drive, trim the drive then the tabs or do a little of both until your dialed in?

[Indyblackhawk]

When I hit 82mph I had the drive slightly up, tabs all the way up hit ~5100-5150 rpms (when the ECM was replaced the rev limiter was bumped up to 5200)

Normally I have the drive up pretty high, nice 200ft rooster then lift the tabs and lower the drive to slightly above all the way down... then progress to slowly lift the tabs little by little

[Indyblackhawk]

yes, have the 1.5

[blackhawk]

Here's how I dial mine in from a dead stop

Drive and tabs all the way down, baby it on plane. Once on plane I raise the tabs until the boat is running "flat". Basically keeping them down to where the boat doesn't porpoise. I then start trimming the drive out until the boat feels lighter and drop the hammer and continue to trim the drive out until I hit about 4000 rpm. I then raise the tabs and drive a little at a time(back and forth between the two) until I get it dialed in according to water conditions.

If you have the drive to far in and lift the tabs you may get some bow steer which may be whats happening. Just a thought.

[Indyblackhawk]

Just got back from a run... mostly kept it in the low 70's..... Had one WO run; 83.9mph (GPS) 85 (speedo) bumping the rev limiter @5200. Very scary at this speed but it was glass smooth out so I felt it was safe to attempt