Ace: A Fast 12 ft Outboard Runabout Without a Building Form
William D. Jackson's Ace skips the building form, seats five and runs from 32 mph on a 16 hp outboard to 50 mph on a 40 hp.
Ace is a small runabout with a big appetite for speed. At 12 ft 4 in (3.8 m) with a 5 ft 9 in (1.75 m) beam, it seats five, yet the original figures show 32 mph with a 16 hp Evinrude, 36 mph with a 25 hp and 50 mph with a 40 hp Mercury. Plywood planking goes over a clever two-frame longitudinal-beam framework, and there is no building form to make. It suits a builder who enjoys a lively ride.
Ace at a glance
| Detail | Ace |
|---|---|
| Type | Outboard runabout |
| Length | 12 ft 4 in (3.76 m) |
| Beam | 5 ft 9 in (1.75 m) |
| Capacity | 5 persons |
| Construction | Plywood planking over a two-frame longitudinal-beam frame; hi-lift bottom; no building form |
| Power | 16 hp Evinrude: 32 mph; 25 hp: 36 mph; 40 hp Mercury: 50 mph |
| Designer | William D. Jackson |
| First published | Boat Builder's Handbook, p. 65 |
| Craft Print | No. 233 |
| Plan sheets | 12 |
What makes it quick
The hi-lift bottom helps the hull rise and plane early, which is how a 12 ft boat turns modest horsepower into impressive speed. The speed table, from 32 mph at 16 hp to 50 mph at 40 hp, shows how responsive the shape is. Two frames joined by longitudinal beams form a strong, light skeleton, and skipping the building form saves lumber and floor space. Twelve detailed sheets help you get the framing right.
The original plan sheets
These are the 12 original sheets, scanned from the magazine. For building, use the full-size PDF in the download section below.
Who designed it
William D. Jackson drew Ace for the Boat Builder's Handbook, page 65, as Craft Print 233. The twelve sheets cover the two-frame longitudinal-beam structure, the hi-lift bottom and plywood planking.
Before you build
- Treat 40 hp as the ceiling and remember that 50 mph in a 12 ft boat needs experience and calm water.
- Fit flotation and secure the steering cables firmly, since a fast runabout needs reliable control.
- Load five people evenly and slow down before turning sharply.
Download the plan
All twelve Ace plan sheets in one file, ready to print at full size or follow on a tablet in the workshop.
Download the complete plan (PDF, 12 sheets, 6.6 MB)
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