The type and size of docks allowed on Winnipesaukee is strictly regulated by the NH DES Wetlands Bureau. With 75' or more of lake frontage, the state allows construction of a 6' wide by 30' long permanent dock or a 6' wide by 40' seasonal dock. Also, if dock pilings are able to be driven into the lake bottom to a satisfactory depth at your location, I do not believe you are allowed to construct a crib dock. Exceptions may be made based on a "demonstrated need".
The installation of a new dock requires a Wetlands Bureau permit, and the addition of a canopy such as the ones shown in your photos requires a permit as well.
I'd suggest you check out the NH DES Wetlands Bureau's web site for more information. A couple good places to start would be:
http://www.des.state.nh.us/factsheet...ands/wb-12.htm
and
http://www.des.state.nh.us/PermitGuide/