The Jeanneau Sun Fast 31 1990 vs Jeanneau Sun Odyssey 30i 2008 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 Sun Odyssey 30i 2008 measures 29,6 feet overall (2008), giving it roughly 4,2 additional feet of deck space compared to the Jeanneau Sun Fast 31 1990 at 25,4 feet (1990). Weight tells a clearer story for trailering families: the Jeanneau Sun Odyssey 30i 2008 tips the scales at 8 697 lbs — 1 863 lbs less than the Jeanneau Sun Fast 31 1990 at 6 834 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.

Both boats share a closely matched power ceiling — 18 hp for the Jeanneau Sun Fast 31 1990 and 21 hp for the Jeanneau Sun Odyssey 30i 2008. 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. Both carry nearly identical fuel loads — 13 gal and 13 gal — so range won't be a tiebreaker here.

For family outings this is probably the sharpest distinction between the two. The Jeanneau Sun Odyssey 30i 2008 is rated for 9 passengers, while the Jeanneau Sun Fast 31 1990 caps at 7. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Jeanneau Sun Odyssey 30i 2008 could be the deciding factor.

Both boats sit in a similar displacement bracket — 6 834 lbs for the Jeanneau Sun Fast 31 1990 and 8 697 lbs for the Jeanneau Sun Odyssey 30i 2008. Comparable displacement means broadly similar seakeeping behaviour and load capacity, though hull form and ballast ratio will still produce noticeably different sailing characteristics.

Both boats draw a similar depth — 5,8 ft and 5,8 ft respectively. Marina access and anchorage options should be broadly equivalent between the two.

The Jeanneau Sun Fast 31 1990 uses Sloop rigging.

Hull speed is rated at 7,0 knots for the Jeanneau Sun Odyssey 30i 2008 and 6,7 knots for the Jeanneau Sun Fast 31 1990. For extended cruising, water capacity matters: the Jeanneau Sun Odyssey 30i 2008 carries 42 gallons versus 26 gallons on the Jeanneau Sun Fast 31 1990 — a significant advantage on longer passages where watermaker or provisioning stops aren't guaranteed.