Minimax: An 8 ft Two-Sheet Plywood Hydroplane Plan
William D. Jackson's 8 ft hydroplane for two, built from two plywood sheets without a form, with air chambers for 900 lb.
Minimax squeezes a lot of fun out of very little plywood. This 8 ft (2.44 m) hydroplane with a 4 ft (1.22 m) beam is built from just two 4 x 8 sheets of 1/4 in plywood, with no building form needed. Air chambers support 900 lb, and it carries two people. Put a 3 hp outboard on it and it reaches about 15 mph; it accepts up to 15 hp. With twenty-one sheets of drawings, it is one of the most thoroughly explained small boats around.
Minimax at a glance
| Detail | Minimax |
|---|---|
| Type | Hydroplane |
| Length | 8 ft (2.44 m) |
| Beam | 4 ft (1.22 m) |
| Capacity | 2 persons |
| Construction | Two 4 x 8 sheets of 1/4 in. plywood; no building form; air chambers support 900 lb |
| Power | 3–15 hp outboard; 15 mph with 3 hp |
| Designer | William D. Jackson |
| First published | Science and Mechanics |
| Craft Print | No. 255 |
| Plan sheets | 21 |
Maximum fun, minimum material
Two sheets of plywood and no building form keep both cost and setup to a minimum. You can start cutting parts almost immediately, which is a big plus for first-time builders or anyone with limited workshop space. An 8 ft boat fits in most garages, too, so building and storing it rarely needs any special arrangements.
The built-in air chambers rated for 900 lb are a thoughtful safety touch for such a small, lively hull. Reaching 15 mph on just 3 hp shows how efficient the shape is, while the 15 hp upper limit leaves room for more excitement once the driver is ready for it.
The original plan sheets
These are the 21 original sheets, scanned from the magazine (the first 12 are shown here). For building, use the full-size PDF in the download section below.
Who designed it
William D. Jackson designed Minimax for Science and Mechanics, issued as Craft Print 255. Few designers contributed more plans to the series, and this one's twenty-one sheets show how much detail he gave readers.
Before you build
- Stick to the 3–15 hp outboard range, starting at the lower end until you know how the hull handles.
- Seal every air chamber thoroughly and test it before closing, since they provide the 900 lb of support.
- Cut parts from the two plywood sheets exactly as the layout shows, because there is no spare stock.
Download the plan
The full Minimax plan in one file: all twenty-one original sheets, ready to print or scroll through on a tablet.
Download the complete plan (PDF, 21 sheets, 13 MB)
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