Both the Weldcraft Marine 21 2011 and the Weldcraft Marine 240 SD 2009 are deep-V 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 - Weldcraft Marine 21 2011 at 21,0 ft versus Weldcraft Marine 240 SD 2009 at 24,0 ft. Weight tells a clearer story for trailering families: the Weldcraft Marine 240 SD 2009 tips the scales at 3 350 lbs - 550 lbs less than the Weldcraft Marine 21 2011 at 2 800 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 Weldcraft Marine 240 SD 2009 tops out at 450 hp. Engine specs for the Weldcraft Marine 21 2011 aren't listed - confirm with a dealer before selecting an outboard.Both carry nearly identical fuel loads - 62 gal and 62 gal - so range won't be a tiebreaker here.
For family outings this is probably the sharpest distinction between the two. The Weldcraft Marine 240 SD 2009 is rated for 7 passengers, while the Weldcraft Marine 21 2011 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Weldcraft Marine 240 SD 2009 could be the deciding factor.
Bottom line: Choose the Weldcraft Marine 240 SD 2009 if your priority is putting more people on the water - it handles 7 passengers and at 24,0 ft it has the deck room to back that rating up comfortably. The Weldcraft Marine 21 2011 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.