I bought a 4x8 sheet of the plastic so there will be definitely be some left over. Not a bad idea but keep in mind my boat is a 30' pleasure cat not a 36-40' wave crushing race boat, it weighs less & he plans to double up the material where the ram brackets attach. My understanding is you want the tab to have a little give. I'm trying to eliminate the midrange hop, those guys run the tab down on the straight aways which provides more lift, getting more of the hull out of the water & a few more mph!

hay mike what about the weight up front

Jim the weight in the bow storage locker in the center over the tunnel did not calm the hop any & made acceleration slower. Those props have some major bite & really want to launch the boat upwards. Best I can tell there's not enough aero lift at the 60-80mph speed to maintain thus the hop as it starts the cycle all over again.

The direction you are going makes sense but I believe I will have to lose so much diameter that my top end will ultimately suffer.

i here ya on the top end loss but you of all people should know performance is a bit of compromises i would much rather have drag race acelleration than just flat out top end top end is probly 5% of your total boating life thats not very much and if i get beat i will go home and put on the big props and come back and get the job done and when the guy ask you what you did tell him you put the two plug wires back on that fell off

Agreed on the importance of top end & percentage spent there but I see myself losing 15+ mph going to the small Dia props & already have good acceleration based on my gear ratio.

A few pics of the transom w/ trim tabs & swim platform removed, holes filled & painted.

Rams are from the tabs but Latham furnished the custom mounts & bracketry!

Now that the boat is back & parts in house he'll begin fabricating the Tunnel Tab itself

Ben sent me a template to have one of my fabricators whip up some tunnel tab side pieces that will help trap more air when the tab is lowered making it that much more efficient. Made out of .250 6061 Alum, they'll thrubolt to the transom on each side of the tunnel just above where the hull sits on the trailer bunks. Plan to paint or powdercoat them white to match transom & tab.

Very cool Mike. Let me know if you need any help, I can blast over and give you a hand.

Alas the long overdue follow up comments on the addition of the tunnel tab.

Adding the tunnel tab gets the BIG THUMBS UP totally eliminating my 60-80mph pleasure cruising porpoising problem w/o sacrificing any performance. It's a huge improvement over tucking the drives in & using the tabs to try & pin the boat down which is exactly how it felt previously.
Using the drives & trim tabs bound the boat up & had it bow steering.

The tab ended up approx 48" wide by 27" deep. We weren't able to use the custom fabbed side pieces since the first 1.5 - 2" edge around my tunnel is foam core & no way to attach the pieces securely. While those components may have increased the overall efficiency the tab itself is plenty efficient. Once I approach the 80mph speed range the tab can be raised all the way up as if it doesn't exist which has been the practice to date as it's my understanding that turning w/ the tab down can spell disaster.

Ben @ BAR Marine did a nice job w/ the totally custom install. I want to believe we even shed a few lbs by eliminating the swim platform & trim tabs. Had NO CLUE trim tabs weighed as much as they do.

Saw a video of the boat running next to the 32 cats azz in the jacksonville run. Boat looks great!