Trim issues after installing Seakeeper

Will a Frigibar filled with beer on the bow help?

Don't make more mistakes to make up for the ones you've already made. You added a bunch of stern weight so the first thing you know of all of this is that you'd need a different prop. Until you get it propped right, don't start making other changes. One thing at a time.

What do you mean a naval architect was consulted? Did they design the addition or does this just mean you casually spoke to one. I can't imagine a naval architect who would tell you adding that weight wasn't going to change anything. If he did, then tell him to now correct the situation.

I can tell you why Seakeeper is stand offish. They don't take installation responsibility. They have authorized dealers who will. Did you work through their Chicago sales person, Bryan Billic?

Regardless, I wouldn't touch tabs, I wouldn't change anything until I tested some different props. Hopefully there is a local prop shop that will let you try some different ones.

One problem on installations such as this is that lowering the stern 2" may mean nothing on some boats, but 1" may be very significant on another. Realize among other things when you raise or lower the stern it's quite common for the trim tabs to require adjustment or raising or lowering. You lowered where they are.

I'd really recommend finding a good experienced shipyard. You aren't demonstrating the experience necessary for what you've undertaken. I wouldn't have it either, so not being critical, just observing.

I have added a 1" or so spacer (I had the yard do it) on several boats and it made a significant impact on trim on boats that needed it. It was cheap, thick starboard blocks with the mounting holes drilled in them. I would go in this direction. Every Carver I've ran needed ALL tabs fully down to perform and could have used more tab. I'd go this route first, then take 2" pitch out of the props. Any weight you can remove from the stern and get as far foward as possibly helps greatly. Losing any weight out of the stern also helps greatly.

As for the props, it sounds like a shop custom tweaked them to get them where they were and the work they did was right (added more camber near the hub for lift) and the speed you had and your prop shop took them back to a traditional shape losing the extra lift the last shop put in them. I've had Arneson and other props tweaked and the camber changed in different area's to get the boat to perform differently.

What does the yard you're working with recommend?

Changing the props may be the most expensive but it's also inevitable. However, I was recommending trying some different ones before paying if you could find a prop shop that would work with you. The naval architect's focus, per your words, was the structure and stringers, not the change in weight or weight distribution. Changing the tabs will allow you to change the running angle and that certainly will be beneficial. I still think after that you'll need to change props.

120-150 rpm isn't that far off and if the engines are electronically controlled, it's better to be low on turns rather than run into the governor when estimating prop changes. I'll side with the group recommending correcting the wheels as a higher priority and as you say, inevitable. Your engines are making all the power they can now and while they aren't getting full WOT rpms, correcting the props will more than likely do nothing to top speed, all you will be doing is changing what speeds you make at what rpm. Just as an example say you're making 23 knots at 1900, after taking out 2" you'll make that same 23 knots at 2050 but will be able to achieve 2350 WOT so your engines are not overloaded. You may get some trim changes by playing with tabs and weight distribution but they will likely not affect speed or engine rpms very much.

Bladders are certainly a viable option to move fluids but they should be done "right". I recommend using ones custom made to fit the coffin they are going in, and that coffin has to be strong enough to support the load. "Pillow", or empty bag bladders can have sloshing issues but there are porous foam-filled ones available (for both water and fuel) that alleviate that issue. Be warned, they aren't inexpensive, last ones I bought ran about $14-15 per gallon for custom made but they will hold up. I use nothing but bladders forward of midships on our newbuilds but from experience (and measurements) I expect 10G impact loading in those areas. Here's a couple pics of a fuel bladder being installed in a coffin on a fast (47+ knot) 63 sportfish we built, it's being vacuumed down to shrink it. 8 years of service so far with no issues.

I've used these http://store.interstateproducts.com/products/Fuel-Bladder-Tanks and ATL, both with excellent results. (Hope that didn't violate terms Carl!)