The Magnum 12

Magnum 12



The plans have all the information you need to build your own boat... Each plan contains all the construction drawings, everything you need to build your boat.
Plus.... you can also join our private subscription based BOAT BUILDING FORUM if you wish, to assist with your build

The plans are printed on 2ft by 3ft paper for normal construction drawings and and full size  paper patterns.
By using the full size patterns and detailed plan sheets, the parts can be accurately marked and cut out. 

Magnum 12 Plans Price
The "Magnum" 12 as the name suggests, offers you a roomy and tough dinghy, the first in a series of lightweight cartoppers.
Perfect for crabbing, fishing, or to just loll the days away, the Magnum 12 is the perfect getaway from it all. With her full forward sections capable of handling a bit of "rough 'n' tumble, generous "flair" to keep you dry and loads of storage compartments, the Magnum 12 provide's excellent stability when fishing or underway. Overall, the Magnum 12 is more than capable to suit your fishing and holiday needs.
As a 12 foot  stitch and glue plywood car-topper, the Magnum 12 has made the average camping trip extraordinary. Being able to fit atop a four wheel drive, the Magnum 12 can turn a camping trip with the family into a great adventure. Perfectly suited for any river, estuary or lake adventures and the perfect camping companion, the Magnum 12's innovative design for stability when fishing and, having a v-shape hull means these boats are able to cope comfortably with choppy waters.
With features that include front and rear bench seats, front deck, bilge sump, flat floor and ample storage space, the Magnum 12 will complete any camping trip, but also expand your adventures to the water.
Magnum 12
Magnum 12


- Overall Hull length ......12 ft ( 3.65m)
- Beam ...... 4ft- 9in (1.44m)
- Deadrise @ Transom ...... 7 degrees
- Engine shaft length ...... S/S (15")  ... Optional L/S (20")
- Fuel Capacity ...... Portable Tank
- Approx Hull weight (Pending Builder and materials) ... 146 lbs (66 kg)
- Recommended Hp ...... 9.9 - 15 Hp 
- Construction …. Epoxy Fibreglass Plywood Composite Construction
Australian Builders Plate Compliant


The following list of materials is approximate and intended for calculation of approximate costs. We offer no guarantees of accuracy. The list is for all plywood in the construction of the hull, deck and interior. Allowance has been made in the quanties for about 10% wastage. Resin and glass quanties are only approximate.
6mm (1/4") - 8 Sheets
RESIN AND GLASS (For coatings and reinforced areas)
Epoxy Resin & Hardener - 18 kg (4.75 US gal)
195gm (6oz) cloth - 24 sq.m ( 29 sq.yards)
1 kg (2.2 lbs) glue powder (Cabosil)
1 kg (2.2 lbs) Q-cells (fairing Powder)
The materials list above covers all the supplies for the boat as designed.
Useage of materials may vary due to several factors. For example, a experienced builder will use less resin. Our resin calculations are based on a 50% glass content. Options, customization and variations within your build will also effect the bill of materials and outcome.

Anyone can Build a Boat. Its that Easy

Just about anyone can build a boat using the Bowdidge Marine Design Plywood Composite system. This method eliminates many members that ordinarily require fitting, fairing, and beveling. Thus, it's ideal for beginners. A jigsaw and drill are about the only power tools required. The resulting boat is incredibly light weight, strong, and durable.

This quick and easy boatbuilding method consists of plywood planking panels cut to shape from patterns in the plans which are "stitched and glued" together at the seams. Such a boat can be assembled in a matter of hours after cutting out the parts.

The stitching is done with plastic electrical ties passed through small holes along seam edges. These are zipped tight to hold the panels together. The glue is then applied between the stitching and also on the inside in a cove-shaped fillet along the seams, along the outside and inside. After curing, the "stitching" is removed and the gaps filled. Then the hull is covered in glassed.

Plans for all our designs include instructions, material layouts, and material listings. In addition, the patterns provided are precise, since they're taken from the actual 3D modeling and CAD systems.