Both the Voyager Marine 18 ft. Sport Fish 2011 and the Voyager Marine Supreme Fish Deluxe 2009 are pontoon designs, both built in aluminium, so 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 - Voyager Marine 18 ft. Sport Fish 2011 at 18,0 ft versus Voyager Marine Supreme Fish Deluxe 2009 at 20,0 ft. At 1 450 lbs and 1 550 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 - 75 hp for the Voyager Marine 18 ft. Sport Fish 2011 and 90 hp for the Voyager Marine Supreme Fish Deluxe 2009. 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 Voyager Marine Supreme Fish Deluxe 2009 is rated for 10 passengers, while the Voyager Marine 18 ft. Sport Fish 2011 caps at 8. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Voyager Marine Supreme Fish Deluxe 2009 could be the deciding factor.
Both are 2-tube and 2-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: Choose the Voyager Marine Supreme Fish Deluxe 2009 if your priority is putting more people on the water - it handles 10 passengers and at 20,0 ft it has the deck room to back that rating up comfortably. The Voyager Marine 18 ft. Sport Fish 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 8 that costs less to run day-to-day.