I owned a 1981 Atlantic 44 from 2001 until 2007. Lived aboard in NY for 6months a year during the summers. The boat had Perkins 6.354's of 130HP each and carried approx. 600 gals of fuel. However, the port wing tank had a leak so it was drained and shut down. While the stbd tank did not leak, I did not use it either to keep the boat balanced. The center tank in between the stringers held 240 gals so more than enough. Loved the overall layout of the boat. I would look closely at all the tanks when purchasing.
The hull is a Hargrave design and is fabulous in a seaway. We returned in 6-8 foot seas from Manasquan to East Rockaway in 2005 and the ride was very stable (certainly not comfortable) and we never felt endangered. The boat is essentially the same as the Hatteras 43 motoryacht internally. Only difference on the exterior is the Hatteras is a flush deck all around while there is a step down from the aft deck to the gunwales going forward.
With the Perkins engines I had complete access all around each engine and was able to basically work on my knees and remain almost erect. Great engine room.
With these engines I operated at about a 9kt cruise. I belive with the Cats you be cruising at 14-16.
If my wife hadn't gotten tired of living aboard I would still own this boat.
Hope this helps.
Boatless but always looking