Both the Sea Fox 205BF 2008 and the Sea Fox 21 BF Sport 2007 are modified-V designs, both built in fibreglass, 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 - Sea Fox 205BF 2008 at 20,0 ft versus Sea Fox 21 BF Sport 2007 at 21,0 ft. Weight tells a clearer story for trailering families: the Sea Fox 205BF 2008 tips the scales at 2 400 lbs - 300 lbs more than the Sea Fox 21 BF Sport 2007 at 2 100 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 200 hp, the Sea Fox 21 BF Sport 2007 has a 25-hp advantage over the Sea Fox 205BF 2008's 175-hp ceiling - enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Sea Fox 205BF 2008 carries 60 gallons versus 47 gallons in the Sea Fox 21 BF Sport 2007. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.
For family outings this is probably the sharpest distinction between the two. The Sea Fox 21 BF Sport 2007 is rated for 8 passengers, while the Sea Fox 205BF 2008 caps at 7. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Sea Fox 21 BF Sport 2007 could be the deciding factor.
Bottom line: Choose the Sea Fox 21 BF Sport 2007 if your priority is putting more people on the water - it handles 8 passengers and at 21,0 ft it has the deck room to back that rating up comfortably. The Sea Fox 205BF 2008 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 7 that costs less to run day-to-day.