The Jeanneau Sun Odyssey 349 2018 vs Jeanneau Yachts 51 2016 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.
Size is the most obvious dividing line here. The Jeanneau Yachts 51 2016 measures 50,6 feet overall (2016), giving it roughly 17,5 additional feet of deck space compared to the Jeanneau Sun Odyssey 349 2018 at 33,1 feet (2018). Weight tells a clearer story for trailering families: the Jeanneau Yachts 51 2016 tips the scales at 31 747 lbs — 19 974 lbs less than the Jeanneau Sun Odyssey 349 2018 at 11 773 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 power gap is worth calling out. Rated to 110 hp, the Jeanneau Yachts 51 2016 has a 89-hp advantage over the Jeanneau Sun Odyssey 349 2018's 21-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load. Fuel capacity breaks the other way: the Jeanneau Yachts 51 2016 carries 63 gallons versus 34 gallons in the Jeanneau Sun Odyssey 349 2018. 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 Jeanneau Yachts 51 2016 is rated for 15 passengers, while the Jeanneau Sun Odyssey 349 2018 caps at 10. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Jeanneau Yachts 51 2016 could be the deciding factor.
Displacement is where these two sailboats genuinely part ways. The Jeanneau Yachts 51 2016 displaces 31 747 lbs — a 19 974-lb difference over the Jeanneau Sun Odyssey 349 2018 at 11 773 lbs. That gap separates two entirely different categories of sailing: the heavier boat is built for offshore passage-making and load-carrying, while the lighter hull rewards performance sailing and easier handling in lighter air.
Both boats draw a similar depth — 6,6 ft and 7,6 ft respectively. Marina access and anchorage options should be broadly equivalent between the two.
The Jeanneau Sun Odyssey 349 2018 uses Sloop rigging. For auxiliary power the Jeanneau Yachts 51 2016 carries a 110-hp engine against 21 hp on the Jeanneau Sun Odyssey 349 2018. Motoring range and ability to punch through a foul current or enter a tight marina under power will favour the more powerful installation.
Hull speed is rated at 9,1 knots for the Jeanneau Yachts 51 2016 and 7,4 knots for the Jeanneau Sun Odyssey 349 2018. For extended cruising, water capacity matters: the Jeanneau Yachts 51 2016 carries 169 gallons versus 54 gallons on the Jeanneau Sun Odyssey 349 2018 — a significant advantage on longer passages where watermaker or provisioning stops aren't guaranteed.
Bottom line: The Jeanneau Yachts 51 2016 is the offshore and bluewater choice — at 31 747 lbs displacement and 51 ft it has the load capacity, range, and seakeeping for extended passages. The Jeanneau Sun Odyssey 349 2018 at 11 773 lbs is the more nimble, accessible option — easier to single-hand and better suited to coastal and inland sailing.