Design and Construction
The fiberglass hull measures 31 feet overall, with a 10.92-foot beam and a fin keel. Its proportions are moderate: the length-to-beam ratio is 2.87, while the ballast ratio is 40 percent. A displacement-length ratio of 230 places the boat in the “moderate racer” classification.
Wetted surface is about 333 square feet. An immersion rate of roughly 989 pounds per inch means the boat settles predictably as weight is added. The capsize screening value is 2.10, explicitly placing the 3100 outside the range for ocean-race acceptance. That is a clear offshore limitation, rather than a criticism of the boat’s composure in coastal waters.
Rig and Handling
Jackett equipped the 3100 with a conventional masthead-sloop rig. The sail-area-to-displacement ratio is 18.7 using the ISO reference sail and rises to 22.1 with a 135 percent genoa. That useful increase confirms the boat’s appetite for a working jib in breeze.
The standing and running rigging follow predictable mid-1990s specifications. The mainsail, jib, and spinnaker halyards are each 96.8 feet long and 3/8 inch in diameter. Genoa and jib sheets are 31.3 feet long and 1/2 inch. The mainsheet measures 78.3 feet, and the spinnaker sheet is 68.9 feet.
The theoretical displacement hull speed is 6.8 knots, setting the boat’s upper limit under sail or power. A Motion Comfort Ratio of 20.8 suggests a settled ride in a chop, without implying that the 3100 is a heavy offshore passagemaker.
Accommodations and Interior Volume
Within its 31-foot hull and 10.92-foot beam, the 3100 offers moderate coastal-cruising interior volume for its class. Its 40-percent ballast ratio implies a substantial interior mold compared with featherweight racing boats of the same length.
Verdict
The Tartan 3100 is a coherent Tim Jackett design from Tartan’s mid-1990s catalog: a fiberglass, fin-keel masthead sloop with moderate-racer characteristics and a comfort-oriented displacement profile. Its screening numbers don’t qualify it as an ocean racer, but its rig and ballast figures describe a boat intended for club racing and weekend cruising in sheltered waters.
Pros
- Designed by Tim Jackett and built in fiberglass by Tartan Marine, Ltd., with a fin keel
- Moderate-racer displacement-length ratio of 230 and a 40-percent ballast ratio for stable handling
- Meaningful performance gain with a 135 percent genoa, raising SA/D to 22.1
Cons
- Capsize screening value of 2.10 excludes it from ocean-race acceptance
- Theoretical hull speed is capped at 6.8 knots
