Bertram 54 Sport fish, good, bad ugly??

Rotted decks will be your main concern. Check foredeck, FB deck, cockpit decks for structural integrity and no water. Rotted fuel tanks is another, especially the cockpit tank. Bad wiring at that age. 12v92's another issue. They did good on a head sea, roll on a beam sea, and ungodly on a beam sea on the troll. I managed one for a while, never loved them. Always have to step on one piece of machinery to access another..........never really cared for them. But IMO a 1988 54' Bertram will be a huge money pit....... your best bet would be to go to a late 1990's, early 2000's Post 50' with 820 MAN's and never look back......much more efficient and a better boat ALL of the way around.

I had an 87 42 Bertram and its tanks were fiberglass. I have come to question some of my memories but I believe I am correct on this. Capt J mentioned bad wiring. I did have a rotary switch get real hot. If I hadn’t caught it would have started a fire. I don’t know if that is specific to rotary switches. I also felt that Bertram didn’t make the shafts big enough but it is possible my issues were something else. They were 1 3/4 with 375 hp engines with 2 to1 twin discs. I would buy an older bertram again but I would do it knowing most all systems if not upgraded will have to be upgraded. Not cheap.

That sounds just right, also according to my props/shafts calculator.
Ok, shaft diameter also depends on the specific type of steel used, shaft length, and other minor parameters.
But by and large, I wouldn't call that not big enough to handle 375hp.

The tanks are aluminum on a 1988 54' Bertram. 2 in the front of the engine room in a good location (high above bilge water and not near ER vents). The aft tank usually goes bad on them because it's under the cockpit sole and close to the bilge water. Bottom line is there are a ton of systems that should be replaced on most 1988 sportfish. Old galleymaid toilets that are constant headaches, does it make sense to buy a rebuilt pump at a $1000 or a complete new raritan toilet (but takes more labor and parts to install), old wiring, old gauges, old electronics, a/c's, decks that are prone to water intrustion and rot, deck hatches, and the biggest are 12v92's.......it'll take you 4 months just to get all of the rebuild parts to rebuild one and then you're dealing with rebuilt liners......and engines that'll need to be rebuilt 900-1000 hours later........Then you want to burn 90 gph to do 21 maybe 22 knots......or 60 gph to do 26 knots in a 50' post that doesn't half half these issues to deal with and motors you'll get 7,000 hours out of before needing a reman. and aren't leaking oil all over your bilge or noisy and stinky. If it's a towered boat, that thing will roll like crazy on the troll.

I'd just bring a caliper instead!

The mid 90's-2006 54' Hatteras is an animal. It is an excellent riding sea boat and build quality and fast. I ran one (a 2004) with a tower a lot, and it rode incredibly well and was a much better boat all of the way around. I ran that boat at 32 knots in 6' seas on the bow coming out of the inlet and then on he beam for 150nm one day and it never once pounded.

The Bertram has a very deep V all of the way back, on the troll or running with a beam sea they rolled very well. The 57' Bertram I also ran 1000's of miles, it was a better riding boat especially on the troll, than the 54' but the COG was too far forward (at least the one I ran with single generator, hard top boat), especially since it had a single 1700 gallon fuel tank at the front bulkhead of the engine room, anything more than 1/2 fuel and it ran like a submarine. Never ran a 63', but would never touch a 57' or 63' due to dozens of them structurally coming apart, including the new at the time 57' that I was running around, owner got rid of it after a year and bertram doing fiberglass work on it twice.

I'd love to scoop me up a 50 Post!

Yeah, the center tank screwed up the COG on the Bertram 57' and with 1/2 fuel or more the boat is a complete submarine, extremely wet. I did well over 1500 NM's on one I managed. Boat still rolled pretty good on the troll, but not at cruise due to it's 31+ knot cruise speed giving it more stability at cruise, however you'd get a 5 gallon bucket of water on the enclosure every 2 minutes in a 3' sea.

The GT59' did NOT replace the 54' GT. The 59' GT replaced the 60' GT. The 54' GT they still made a year or two after the debut of the 59' GT. The earlier 54's were a better boat than the Bertram 54'.