A 1955 is 4MM-HR. A 56 is 6MM-HR. Coils are no longer available however by filing down the sides of the coil laments to 7/16 you can use the OMC stile coils as substitutes. Much the same as in this video. https://youtu.be/OxPHe8EPe1Q?si=tjv5MZrSUTP-pJaf
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.