Offshoreonly.com - '03 356 w / 500 EFI's Top SPEED ?????

In 2003, Sonic started the Baltek process of Infusion. (Vacuum Bagging the hulls.) There were some boats that had some issues with cracks in the resin/gelcoat, so look the boat over carefully. In 2003, I believe they were only doing the hulls like this. The cabin liner and deck were not vacuum bagged. The owner in 2003 was cutting some corners and they were experimenting with the new process and it showed in some boats.

The 356 and the 386 are pretty much identical from the steering wheel forward. The extra couple feet comes in the engine compartment or extended cockpit that you see in some 386 boats. Some 386's have huge cockpit with a U-shaped rear seat. Some have triple engines so the cockpit is smaller like the 356.

Some/most 356s had issues with porpoising. This has to do with the notched transom. The boat gets up on plane and wants to lift most of the nose out of the water, and the hull searches for this missing notch of the transom/aft portion of the hull to run on. Well, when its not there, the boat's nose falls a bit, and this creates a vicious cycle we call porpoising. Sometime in 2003, Sonic took the notch out of the 356 (in other words filled it in for a square transom). In most boats with a notch, its there to provide cleaner water for the props much like a setback box does; however it does have its drawbacks.

The 356 had the most porpoising issues, but its not a bastard boat. Most owners found a way to set the trim and keep the boat performing well; otherwise you would see all of them for sale. Best idea is to mark the window of the trim indicators with a Sharpie marker on the the ideal trim settings and leave them there.