When two boats share the same hull type — in this case both the Weld-Craft CDL 56 (18 ft.) 2009 and the Weld-Craft UVCDS 36 (12 ft.) 2010 are flat 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?
The power gap is worth calling out. Rated to 40 hp, the Weld-Craft CDL 56 (18 ft.) 2009 has a 25-hp advantage over the Weld-Craft UVCDS 36 (12 ft.) 2010's 15-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Weld-Craft CDL 56 (18 ft.) 2009 is rated for 5 passengers, while the Weld-Craft UVCDS 36 (12 ft.) 2010 caps at 3. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Weld-Craft CDL 56 (18 ft.) 2009 could be the deciding factor.
Bottom line: Choose the Weld-Craft CDL 56 (18 ft.) 2009 if your priority is putting more people on the water — it handles 5 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Weld-Craft UVCDS 36 (12 ft.) 2010 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 3 that costs less to run day-to-day.