Re: restoring my old new 71 starcraft center console
Your going to have to repair those cracks. I'd opt for welding them up, and adding two side supports or angles to that knee brace. That rear brace gives the transom most of it's strength. It looks to me like there was a lot of movement in the sheetmetal in that hull for a long time. It must have really took a pounding.
Interesting splashwell in that boat, I've had several 18' hulls now, several from 1967 to 1974, none have had those extra boxed in corner pieces that narrow the inside of the splashwell area. All of mine were just flat bent panels with no angular corner boxes.
I did have a 1995 18' that had those in it, it was also the same color blue. That boat had the same broken single knee brace and both gunwales were torn where they met the splashwell area. That boat had significant saltwater corrosion down the keel so I sold it as is.
All of my pre 1972 Starcraft aluminum hulls had their serial number plate attached to the inside of the transom near the top upper corner on the port side. The plate has always been attached to the wood itself with round headed tacks or 'rivets'.
All 1972 and up have had a small plate tack welded to the right outer transom in the wing area. Newer models didn't have this smaller plate but would have a larger, 4x5 or so sized Coast Guard certification plate.
If your state is like NJ, chances are somewhere along the line the title got lost, it got sold and someone got a reassigned title. Who ever assigned the title or did the inspection thought it looked like a 1971 for some reason. (I've got a 1964 that the state decided was a 1980 model).