When two boats share the same hull type — in this case both the Zodiac Pro Open 650 2008 and the Zodiac ProJet 420 TC4 2008 are inflatable rigid designs with rigid inflatable 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?
Size is the most obvious dividing line here. The Zodiac Pro Open 650 2008 measures 21,0 feet overall (2008), giving it roughly 8,0 additional feet of deck space compared to the Zodiac ProJet 420 TC4 2008 at 13,0 feet (2008). Weight tells a clearer story for trailering families: the Zodiac Pro Open 650 2008 tips the scales at 1 388 lbs — 484 lbs more than the Zodiac ProJet 420 TC4 2008 at 904 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 Zodiac Pro Open 650 2008 has a 77-hp advantage over the Zodiac ProJet 420 TC4 2008's 98-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Zodiac ProJet 420 TC4 2008 is rated for 6 passengers, while the Zodiac Pro Open 650 2008 caps at 5. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Zodiac ProJet 420 TC4 2008 could be the deciding factor.
Bottom line: Choose the Zodiac ProJet 420 TC4 2008 if your priority is putting more people on the water — it handles 6 passengers and at 13,0 ft it has the deck room to back that rating up comfortably. The Zodiac Pro Open 650 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 5 that costs less to run day-to-day.