When two boats share the same hull type — in this case both the Sea Fox 185BF 2010 and the Sea Fox 21 BF Sport 2007 are modified vee designs with fiberglass 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 Sea Fox 21 BF Sport 2007 measures 21,0 feet overall (2007), giving it roughly 3,3 additional feet of deck space compared to the Sea Fox 185BF 2010 at 17,7 feet (2010). At 15 lbs and 21 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.
The power gap is worth calling out. Rated to 200 hp, the Sea Fox 21 BF Sport 2007 has a 60-hp advantage over the Sea Fox 185BF 2010's 140-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 21 BF Sport 2007 carries 47 gallons versus 27 gallons in the Sea Fox 185BF 2010. 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 185BF 2010 caps at 6. 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 185BF 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.