I hope someone can help. I have a 1977 Thompson Voyager 259, (title says 23ft-measures at 24') that has two 4 cylinder Volvo Penta engines. I can't find information anywhere about this thing! One marine parts supplier told me that I "just think there are two engines, that there is really just one"...I apologize for being new to this and having to ask for help, but there really are two Pentas, and I have searched every term I can think of and still come up empty. If anyone has an ideas, please let me know.