Irwin 28 - 4
Description
The Irwin 28 Mk IV is a fiberglass masthead sloop designed by naval architect Ted Irwin and built by Irwin Yachts in St. Petersburg, Florida, from approximately 1977 to 1980. As the final iteration of the Irwin 28 series (Mk I-IV, launched in 1970), the Mk IV refined earlier models with a high-aspect rig for improved upwind performance, enhanced interior ventilation, and minor layout tweaks for better livability. Designed for affordable coastal and day sailing, it targets novice sailors and small families, offering a spacious interior for its 28-foot size, ideal for weekend getaways or short coastal hops (e.g., Florida Keys, Chesapeake Bay). With options for fixed fin keel or keel/centerboard, it’s versatile for shallow waters but not built for blue water without significant upgrades due to its light construction. Approximately 50-75 Mk IV hulls were produced, making it the rarest of the series’ ~200-300 total units.
Construction Details
| Designer | Ted Irwin |
|---|---|
| Builder | Irwin Yachts |
| Length | 28.000 ft |
| LOA | 28.420 ft |
| LWL | 23.000 ft |
| Beam | 9.000 ft |
| Displacement | 7800 lb |
| Max Draft | 4.500 ft |
The standard boat dimensions
| i | 37 ft |
|---|---|
| j | 12 ft |
| p | 31.67 ft |
| e | 9.75 ft |
| p2 | 28.25 ft |
| e2 | 9.75 ft |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| 37 ft | 12 ft | 31.67 ft | 9.75 ft | 28.25 ft | 9.75 ft | - | - |
Sails
| Sail Type | MAINSAIL |
|---|---|
| Luff | * 31.67 ft - (9653 mm) |
| Foot | * 9.75 ft - (2972 mm) |
| Leech | * 32.61 ft - (9940 mm) |
| Tack Angle | * 88 ° |
| Diagonal | * 32.81 ft - (10000 mm) |
| Head (inches) | * 4.5 in - (114 mm) |
| Area | * 159.49 ft² |
| Sail Type | JIBSAIL |
|---|---|
| Luff | * 31.12 ft - (9485 mm) |
| Foot | * 15.93 ft - (4855 mm) |
| Leech | * 26.96 ft - (8217 mm) |
| Percentage LP | * 115 % |
| Length Perpendicular | * 13.8 ft - (4206 mm) |
| Deck Angle | * 12.01 ° |
| Area | * 214.71 ft² |
| Sail Type | GENOA |
|---|---|
| Luff | * 36.95 ft - (11262 mm) |
| Foot | * 19.41 ft - (5916 mm) |
| Leech | * 34.72 ft - (10583 mm) |
| Percentage LP | * 150 % |
| Length Perpendicular | * 18 ft - (5486 mm) |
| Deck Angle | * 4 ° |
| Area | * 332.56 ft² |
| Sail Type | ASYMMETRICAL |
|---|---|
| Luff | 37.5 ft - (11430 mm) |
| Foot | 20 ft - (6096 mm) |
| Leech | 35.5 ft - (10820 mm) |
| Perc LP | * 165 % |
| Area | * 562 ft² |
| Sail Type | SPINNAKER |
|---|---|
| Stays | * 36.95 ft - (11262 mm) |
| MidGirth | * 21.6 ft - (6584 mm) |
| Foot | * 21.6 ft - (6584 mm) |
| Perc LP | * 180 % |
| Area | * 678 ft² |
Disclaimer. Boats are not all the same -- even when produced in the same factory of the same model. Sailrite does its best to publish accurate dimensions, but we often find it worthwhile to have our customers measure their boats carefully before we produce kits for them. You should take the same precautions, especially when the data is not from Sailrite. The information on this site is not guaranteed to be accurate. Sailrite offers this content as a service to our community, but takes no responsibility for the reliability of the data provided.