When two boats share the same hull type — in this case both the Avalon Tropic - 18 Foot 2008 and the Avalon Windjammer 20 ft. 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?
Size is the most obvious dividing line here. The Avalon Tropic - 18 Foot 2008 measures 18,0 feet overall (2008), giving it roughly 16,0 additional feet of deck space compared to the Avalon Windjammer 20 ft. 2009 at 2,0 feet (2009). Weight tells a clearer story for trailering families: the Avalon Tropic - 18 Foot 2008 tips the scales at 1 491 lbs — 1 316 lbs more than the Avalon Windjammer 20 ft. 2009 at 175 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.
Both boats share a closely matched power ceiling — 75 hp for the Avalon Tropic - 18 Foot 2008 and 90 hp for the Avalon Windjammer 20 ft. 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. Both carry nearly identical fuel loads — 24 gal and 24 gal — so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Avalon Windjammer 20 ft. 2009 is rated for 9 passengers, while the Avalon Tropic - 18 Foot 2008 caps at 8. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Avalon Windjammer 20 ft. 2009 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Avalon Windjammer 20 ft. 2009 comes in at 2 lbs per hp versus 20 lbs per hp for the Avalon Tropic - 18 Foot 2008. 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.
Bottom line: Choose the Avalon Windjammer 20 ft. 2009 if your priority is putting more people on the water — it handles 9 passengers and at 2,0 ft it has the deck room to back that rating up comfortably. The Avalon Tropic - 18 Foot 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 8 that costs less to run day-to-day.