When two boats share the same hull type — in this case both the South Bay 520F 2010 and the South Bay 520F TT 2009 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?

On paper these two are close siblings in the size department — South Bay 520F 2010 at 21,6 ft versus South Bay 520F TT 2009 at 21,0 ft. Weight tells a clearer story for trailering families: the South Bay 520F TT 2009 tips the scales at 173 lbs — 157 lbs less than the South Bay 520F 2010 at 16 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.

The power gap is worth calling out. Rated to 175 hp, the South Bay 520F TT 2009 has a 60-hp advantage over the South Bay 520F 2010's 115-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Both carry nearly identical fuel loads — 31 gal and 31 gal — so range won't be a tiebreaker here.

Both boats are rated for 11 passengers — a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.

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.