The Hallberg - Rassy 31 Monsun 1973 vs Hallberg - Rassy 312 1979 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.
On paper these two are close siblings in the size department — Hallberg - Rassy 31 Monsun 1973 at 30,9 ft versus Hallberg - Rassy 312 1979 at 30,1 ft. Weight tells a clearer story for trailering families: the Hallberg - Rassy 312 1979 tips the scales at 10 803 lbs — 1 553 lbs less than the Hallberg - Rassy 31 Monsun 1973 at 9 250 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 — 23 hp for the Hallberg - Rassy 31 Monsun 1973 and 28 hp for the Hallberg - Rassy 312 1979. 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 — 32 gal and 29 gal — so range won't be a tiebreaker here.
Both boats are rated for 9 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.
Both boats sit in a similar displacement bracket — 9 250 lbs for the Hallberg - Rassy 31 Monsun 1973 and 10 803 lbs for the Hallberg - Rassy 312 1979. 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 — 4,7 ft and 5,4 ft respectively. Marina access and anchorage options should be broadly equivalent between the two.
Sailboat comparisons often come down to details that specs don't fully capture — the quality of the standing rigging, the layout of the cockpit, and how the boat feels on a beat in 20 knots. A sea trial on both is strongly recommended.
For extended cruising, water capacity matters: the Hallberg - Rassy 31 Monsun 1973 carries 43 gallons versus 32 gallons on the Hallberg - Rassy 312 1979 — a significant advantage on longer passages where watermaker or provisioning stops aren't guaranteed.
Bottom line: The Hallberg - Rassy 31 Monsun 1973 and Hallberg - Rassy 312 1979 are closely matched on paper. A sea trial on both in representative conditions is the only reliable way to find which one suits your sailing style, home port, and intended cruising ground.