Porpoising 400TF

Chazb

Recruit
Joined
Apr 25, 2016
Messages
1
My wife and I purchased a new 400TF last July and although we love the style and other features of the boat, we were and continue to be very disappointed in the boats handling. From day one, the boat has, with minimal trim on the outdrive, excessive porpoising. Also, if there is a bit of a chop on the lake, the boat seems to skip or bounce off the waves rather than cut through or glide over them. It can be a very rough ride.
We mentioned this to the retailer, Bass Pro's, and was advised to at least get the engine through the 20hr break-in before making any changes to the boat. Needless to say, by the end of the season, we had completed the break-in. Now with the new season upon us, the retailer wishes to take the boat to the lake themselves to see why it has such poor handling. Initially, we did make a prop change from a 19 pitch to a 17 but of course this did nothing to improve the ride and dropped the speed a bit.
Our first trip on the water so far this season was on 4/15/16 and with a calm surface, and very conservative trim on the outdrive, the issue of course still persists. The boat has a Merc in-line 3.0 -4cyl with an Alpha 2.0 drive. Top speed so far is about 34mph/4500rpm.
My suggestion to the Power Pros at Tracker Marine was to install some Smart Tabs on the boat but they are reluctant to do so just yet. They suggested another prop change and possibly a "whale tail" installed on the outdrive. They have been tasked from the factory with operating the boat as well as taking some measurements on the hull and outdrive.
From everything I have read though, the Smart Tabs seem to be the best option at this point. Are there other 400TF owners experiencing the same issues? If so, have you corrected it and how? Thx.
 

Tim in TN

Seaman
Joined
Feb 18, 2010
Messages
55
Hi Chazb. I don't have a 400TF but do own a 2006 Q6. Porpoising was a problem with it too but Smart Tabs made it a whole new boat. Porpoising is nearly eliminated and it can stay on plane at much lower speeds now, which is great for wakeboarding. Best modification I've made to the boat. Highly recommend them !
 

ronq

Cadet
Joined
Mar 15, 2014
Messages
18
Chazb, I second what Tim said. I have a 07 Q6 and installed them before last season. I bought this boat used 2 years ago and had to do something after the first season. There are several Tahoe owners on here that have added them and I haven't seen anyone that didn't love them. That is the only change I made for last season and it's like a completely different boat.
 

Bonus Check

Petty Officer 2nd Class
Joined
Apr 19, 2015
Messages
162
I agree the Smart Tabs are a great mod. My Q6 was not really bad except for the anaconda effect
 

HeavyDinKC

Cadet
Joined
Jun 1, 2016
Messages
14
Chazb, I have a 2011 Q5 and added the Smart Tabs this last off season. Completely new boat. No more porpoising, or bouncing around. As others have said, it's the best modification I've made!
 

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Redrock1

Recruit
Joined
Jun 15, 2016
Messages
1
Chazb, have you made any progress or additional modifications to help correct the tough ride? I'm in the same boat... I purchased a 400tf and I'm having the same issues with my boat. I'm disappointed and wish I would have taken this boat for a test run before purchasing.
 
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maddog2112

Petty Officer 1st Class
Joined
Jul 31, 2009
Messages
252
I will agree with the others. My 06 Q6 was horrible on porpoising and when trying to plane, The bow was way out of the water for what seemed like an eternity! Smart tabs cured it all and the boat planes out almost immediately even with a full boat!
 

Hashi

Chief Petty Officer
Joined
Sep 19, 2007
Messages
502
After 8 years, I finally bit the bullet and drilled holes in my transom for the smart tabs. I haven't gone on the lake to test them yet but plan to do this weekend. From all of the posts and testimonials I've read, I know I won't be disappointed. Just wanted to add a tip from my install. After drilling the holes with the recommended 7/32" bit, you should take the next size larger bit (1/4") and drill to remove enough of the gel coat from around the previously drilled hole. As I was installing the screws, I heard my gel coat crack at each hole from the pressure of the screw going in. I'm afraid the cracks may migrate after time and from the vibration of the engine. I also wanted to make sure the hole was clean after drilling and blew them out with compressed air. Then I cleaned the holes with q-tips dipped in acetone and blew out any residual acetone to provide a clean bonding surface for the 3M sealant. Also, I noticed an install on YouTube where one guy had caulked around the bottom mounting plates. This won't stop water from entering behind the plate because the hole on the larger hinge base is hollow. If you want to waterproof it, you should install caulk into the cavity of hinge and let it cure out. Afterwards, drill out the caulk for the bolt.
 

fish hook

Petty Officer 3rd Class
Joined
Jul 22, 2011
Messages
94
just installed tabs on my 04 Q4 with the 4.3V6. I can tell a big difference but still get some porpoising. Have the 60lb actuators in the 3rd hole - anyone have noticeable gains moving the shock? Which hole would give me more stern lift? would I benefit from 80lb shock?
 

Hashi

Chief Petty Officer
Joined
Sep 19, 2007
Messages
502
just installed tabs on my 04 Q4 with the 4.3V6. I can tell a big difference but still get some porpoising. Have the 60lb actuators in the 3rd hole - anyone have noticeable gains moving the shock? Which hole would give me more stern lift? would I benefit from 80lb shock?


Because the transom on my Q7i tapers down towards the bottom of the boat (keel), I had to adjust my tabs to the second hole. This helps with the performance but noticed some porpoising but not as bad without them. I also noticed that the steering has become more loose. It's like adding full power steering instead of power assisted steering. I over-steered a few times that almost threw me out of the cockpit :eek: I just need to adjust and get used to that. I do plane faster and at slower speeds and eliminated my chine walking. Overall, I'm satisfied with the tabs.
 

fish hook

Petty Officer 3rd Class
Joined
Jul 22, 2011
Messages
94
when I installed them, the directions say they will naturally hang at 25 degrees to the hull - no way, they flopped all the way down. I built a jig to hold them at 25 degrees while lining up the upper shock mounts. Anyone else have this issue? I also replaced the crappy nylon hardware with SS - the problem I saw wasn't so much durability but no locking nut. I think I would've lost my tabs at some point with the plastic hardware
 

girtgist

Seaman Apprentice
Joined
Apr 12, 2011
Messages
30
So six years later, lol
Are their still 400tf owners here and have installed the trim tabs? Any pictures of where you placed the tabs? The stern is far from flat, and kinda rounded on the port and bow sides of the stern. Any recommendations appreciated.
 
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