superstructure design

I am currently building a 50 foot Trawler , but the plans for the upper structure could not be found when I took over the project. Moreover, all the bulkheads are in place and I have finished laminating all the oak beams for the deck and am now trying to figure out a good design for the superstructure so if anyone out there could recommend a good way to do this or has a drawing of the framework or an old plan lying around please contact me. Furthermore, I was also trying to figure out which would be the cheapest way to go- --- I was thinking wood frame and plywood, and Glass, but I am also open to suggestions as wood is extremely expensive now so I also thought maybe even steel, or a lot of people say foam core---any information would greatly be appreciated thanks Douglas-- please feel free to email me at Douglasfurlong@rocketmail.com