When two boats share the same hull type — in this case both the Yellowfin 39 2013 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?
Both boats share a closely matched power ceiling — 1 400 hp for the Yellowfin 39 2013 and 1 400 hp for the Yellowfin 42 2013. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup. Fuel capacity breaks the other way: the Yellowfin 39 2013 carries 55 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.
Both boats are rated for 12 passengers — a good fit for a family of four or five plus guests. Comfort at capacity is another matter; the longer hull typically means more seat options and better weight distribution.
Bottom line: The Yellowfin 42 2013 at 42,0 ft is the right call if deck space, comfort, and entertaining are top of your list. The Yellowfin 39 2013 at 39,7 ft wins on trailering ease, likely lower purchase price, and simpler docking — a solid choice for a buyer who wants more boat for less money.