Knockabout 15
Description
The Knockabout 15 (often called the 15-foot knockabout or similar in plans) is a classic American plywood sailing dinghy/dayboat, typically a simple knockabout design from mid-20th-century DIY/home-build plans (popular in magazines like Popular Mechanics or U-Build-It style publications). It's not a single standardized production model but a type of small, easy-to-build knockabout sloop—lightweight, trailerable, and suited for lake/river daysailing, club racing, or beginner family use. Many were home-built in the 1950s–1970s from plans like the "15-ft. Sailing Knockabout" (e.g., "Tramp" from vintage articles) or Edwin Monk-inspired versions, using plywood with simple frames, clinker or smooth planking, and a basic fractional or masthead sloop rig. No specific designer is consistently credited across all variants (often "unknown" or anonymous magazine plans), but some trace to Edwin Monk or similar Northwest designers for plywood knockabouts. Production was DIY/small shop (thousands built informally, no factory run), with surviving examples rare but occasionally restored as wooden classics.
Construction Details
| Designer | Edwin Monk Jr. |
|---|---|
| Builder | Home Built |
| Length | 15.000 ft |
| LOA | 15.000 ft |
The standard boat dimensions
| i | - |
|---|---|
| j | - |
| p | - |
| e | - |
| p2 | - |
| e2 | - |
| i2 | - |
| j2 | - |
| I | J | P | E | P2 | E2 | I2 | J2 |
|---|---|---|---|---|---|---|---|
| - | - | - | - | - | - | - | - |
Sails
Knockabout 15 - MAINSAIL
| Luff | 17.25 ft - (5258 mm) |
|---|---|
| Foot | 10.33 ft - (3149 mm) |
| Leech | * 19.6 ft - (5974 mm) |
| Tack Angle | * 87.97 ° |
| Diagonal | * 19.79 ft - (6032 mm) |
| Head (inches) | * 4.5 in - (114 mm) |
| Area | 88.95 ft² |
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Knockabout 15 - JIBSAIL
| Luff | 12 ft - (3658 mm) |
|---|---|
| Foot | 5.08 ft - (1548 mm) |
| Leech | 10.83 ft - (3301 mm) |
| Length Perpendicular | 4.58 ft - (1396 mm) |
| Area | 27.51 ft² |
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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.
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