This kind of goes along with some of the other build threads going on right now. I have a 2005 22 Donzi Classic. Actual length of hull is 22' 6". The hull is solid glass and has held up well to real off-shore use on the Great Lakes. I know that this makes for a heavy hull but I will never have to worry about rotten coring. The deck and liner are balsa cored. Transom is non-wood and stringers appear to not be wood also. Now let's say we step up to a 24' off-shore type boat such as a Pantera, Superboat, Banana, etc. Do these all use fully cored hulls? I assume that anything bigger would have to be cored to keep weight down?

It all depends on the builder.
Sometimes bottoms are cored. Sometimes sides are cored. Sometimes neither. Sometimes both.

Technology has changed significantly over time which has also allowed manufacturers to adjust. New materials, vacuum bagging/infusion; etc. etc.

Nortech builds solid bottom boats throughout their entire lineup.

My 24' Baja was balsa top bottom and sides. My 27 Donzi is foam stringers and transom no coaring top or bottom and she is a very light layup. Boat is much lighter than the Baja and the ride shows it...

Surprising answers!!

Here will be probably the most surprising answer. Checkmate used to build a little boat called the Playmate. I think it was 10 or 12 feet long. Like everything else in their lineup, it was fully cored with balsacore.

Panteras are not cored, atleast their 28's are not.

I remember looking at a 29' Envision at Broken Arrow Marine at LOTO. To demonstrate the toughness of the boat, the salesperson jumped up and down on the deck, walked up and down the face of the windshield, and then handed me a cutaway section of hull to show it was pure glass. Damn that thing was thick...and heavy! I had to laugh/cringe at what he was doing to a new boat but that was their LOTO sales pitch on how the boats were made to put up with the rough water. Their thinking was that non-cored boats are stronger. They are definitely heavier!

Joker Powerboats they built solid bottoms in their boats by at least 1 inch thick if not more. A lot of tops sides are cored in many boats. As mentioned depends on the builder and their layup process along with vacuum bagging and so on.. A lot of builders used balsa and or foam coring.

depend's on the year , I had a 2005 and the bottom was solid but the deck and side's had balsa core