Design and Construction
The Irwin 30 has a solid fiberglass hull, a length of 30 feet, and a waterline length of just under 27 feet. Beam is just over 10 feet. She displaces nearly 9,200 pounds, including 4,100 pounds of lead ballast.
The yachtdatabase review gives her a displacement-length ratio of 242 and a length-beam ratio of 2.97. Those figures describe a relatively narrow, moderately loaded hull for her era.
Irwin offered several keel configurations rather than one fixed arrangement. The stub-and-centerboard version combines a fixed stub keel with a retractable board, allowing the boat to work in both coastal and inland waters. Loaded draft with this arrangement is about 4.3 to 4.6 feet.
A shallow fin-keel version draws 3.9 to 4.2 feet. A third, deeper fin option draws roughly 5.0 to 5.3 feet and still clears most marinas. This range of underwater profiles is unusual for a 30-footer. It allowed the same hull mold to serve both shallow-draft gunkholers and sailors who preferred a deeper keel.
Rig and Handling
The Irwin 30 is a masthead sloop with a mast roughly 45.5 feet above the waterline and about 474 square feet of sail area.
Her standing and running rig dimensions are thoroughly documented. The mainsail, jib or genoa, and spinnaker halyards are each about 91.8 feet long and 3/8 inch in diameter. Jib, genoa, and mainsheets use 1/2-inch line, with the mainsheet measuring 75 feet. The cunningham, kicking strap, and clew outhaul use 3/8-inch line in lengths from 11 to 22 feet.
These dimensions fall within the expected range for a 30-foot sloop. Using one size for all the halyards also simplifies replacement.
The hull bottom has about 365 square feet of wetted surface, while the immersion rate is near 930 pounds per inch. The original describes these figures as meaning that she settles predictably under load.
Performance
On paper, the Irwin 30 looks like a willing coastal performer. Her theoretical displacement hull speed is 6.9 knots. Her capsize screening value of 1.88 would, by that formula alone, admit her to ocean racing.
The Motion Comfort Ratio is 25.6. Together with a displacement-length ratio of 242, that places her among moderate racers rather than heavy voyagers. None of these figures makes her a bluewater expedition boat by modern standards, but they do describe a hull tuned more for responsiveness than absolute load-carrying ability.
Keel Variations and Known Issues
The Irwin 30’s range of keel options is the only variation a buyer should note. Because the same hull was sold with stub-centerboard, shallow-fin, and deeper-fin appendages, a particular boat’s draft and behavior underfoot must be confirmed from that hull rather than assumed from the model name.
Sources describe no systemic defects for this model.
Verdict
The Irwin 30 is a late-1960s Ted Irwin design that entered series production in 1976 as a fiberglass masthead sloop. She combines moderate-racer proportions with uncommon keel flexibility for her size. Her documented rig dimensions should simplify upkeep, while the shallow-draft options broaden the range of waters and marinas where she can be kept.
Pros
- Three keel options, including a retractable-centerboard version for thin water
- Solid fiberglass hull, lead ballast, and moderate-racer proportions
- Fully documented rigging lengths and diameters simplify upkeep
Cons
- Capsize screening and comfort numbers place her in coastal rather than offshore territory
- Keel variation means each boat must be assessed according to its particular appendage
