When two boats share the same hull type — in this case both the Zodiac Bayrunner 550 2013 and the Zodiac Yachtline 420 2013 are modified vee 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 Bayrunner 550 2013 measures 18,1 feet overall (2013), giving it roughly 4,3 additional feet of deck space compared to the Zodiac Yachtline 420 2013 at 13,8 feet (2013). At 694 lbs and 602 lbs respectively, both sit in a similar weight class — either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
Both boats share a closely matched power ceiling — 40 hp for the Zodiac Bayrunner 550 2013 and 50 hp for the Zodiac Yachtline 420 2013. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup.
For family outings this is probably the sharpest distinction between the two. The Zodiac Bayrunner 550 2013 is rated for 12 passengers, while the Zodiac Yachtline 420 2013 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Zodiac Bayrunner 550 2013 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Zodiac Yachtline 420 2013 comes in at 12 lbs per hp versus 17 lbs per hp for the Zodiac Bayrunner 550 2013. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Top speed is rated at 42 mph for the Zodiac Bayrunner 550 2013 and 37 mph for the Zodiac Yachtline 420 2013.
Both are inflatable designs, which means they pack down for compact storage, can be carried in a bag, and are dramatically lighter than equivalent rigid hulls. The trade-off is setup time and the need to monitor tube pressure regularly. Tube diameter differs: 1 ft. 8 in. (0.5 m) on the Zodiac Bayrunner 550 2013 vs 1 ft. 6 in. (0.46 m) on the Zodiac Yachtline 420 2013 — larger tubes generally mean more buoyancy and a drier, more stable ride.
Bottom line: Choose the Zodiac Bayrunner 550 2013 if your priority is putting more people on the water — it handles 12 passengers and at 18,1 ft it has the deck room to back that rating up comfortably. The Zodiac Yachtline 420 2013 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.