When two boats share the same hull type — in this case both the Yellowfin 34 2012 and the Yellowfin 42 2013 are deep 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?
The power gap is worth calling out. Rated to 1 400 hp, the Yellowfin 42 2013 has a 350-hp advantage over the Yellowfin 34 2012's 1 050-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Yellowfin 34 2012 carries 45 gallons versus 6 gallons in the Yellowfin 42 2013. 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 Yellowfin 42 2013 is rated for 12 passengers, while the Yellowfin 34 2012 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Yellowfin 42 2013 could be the deciding factor.
Bottom line: Choose the Yellowfin 42 2013 if your priority is putting more people on the water — it handles 12 passengers and at 42,0 ft it has the deck room to back that rating up comfortably. The Yellowfin 34 2012 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 10 that costs less to run day-to-day.