I spent a lot of time researching this for my 2007 marlin .... I wound up getting the original unit repaired, .. I removed it from the boat and brought it to a marine air ( dometic) service guy in NJ. So Far - so Good !!.... I was going to replace it with either a Mermaid or Mabru unit .... I did not want to go less than the original 7 K BTU and I wanted to keep the air intake in the same location ( under the stairs. ) both of these companies make units that will fit the space and the required BTU's....
MABRU SC7K BTU 115V 60hz Marine Air Conditioner Copper Fin (Heating and Cooling) But facing the unit the condenser and the compressor are opposite the original...
The Mermaid 9K BTU best fits the bill ... The compressor and condenser are in the same configuration as the original and the foot print is small ... this would be my choice ... Someone said Citi Marine..... That would also be my choice ....