When two boats share the same hull type — in this case both the South Bay 529CR Upper Deck 2011 and the South Bay 825CPTR TT I/O 2008 are pontoon designs with aluminum construction — the buying decision usually comes down to a handful of practical questions: how many people are you putting on the water, how far do you trailer, and what does your tow vehicle weigh?
The power gap is worth calling out. Rated to 525 hp, the South Bay 825CPTR TT I/O 2008 has a 375-hp advantage over the South Bay 529CR Upper Deck 2011's 150-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the South Bay 825CPTR TT I/O 2008 carries 38 gallons versus 31 gallons in the South Bay 529CR Upper Deck 2011. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
Both are 2-tube and 3-tube pontoon designs respectively. Tube diameter and gauge affect stability and load capacity — more so than most buyers realize when comparing on paper.
Bottom line: The South Bay 529CR Upper Deck 2011 at 29,0 ft is the right call if deck space, comfort, and entertaining are top of your list. The South Bay 825CPTR TT I/O 2008 at 26,0 ft wins on trailering ease, likely lower purchase price, and simpler docking — a solid choice for a buyer who wants more boat for less money.