Bowdidge Marine Designs
Performance  Boat Designs with "Flare"
                                                                                              THE  MAGNUM 12

COMPLETE PAPER BOAT PLANS : For our builders we offer full size printed bulkhead/ frame patterns, printed on 24" wide paper which are taped together to provide fulls size outlines. Using the full size patterns and detailed plan sheets, the parts can be accurately marked and cut out.
All Plan sheets are printed on Architectural D (24" x 36" ) paper except for the full size patterns. Detailed plans consist of  11 sheets which detail all aspects of construction.

   The Magnum 12 Specifications 

Overall Hull length = 12 ft ( 3.65m)
Beam = 4 ft-9in (1.44m)
Rec Horsepower = 9.9-15 Hp
Deadrise @ Midship = 7 degrees 
Engine shaft length = S/S (15")
Fuel Capacity = Builders Choice 
Approx Hull weight (pending builder) = 132 lbs (60 kg)
Max Persons = 4

Magnum Plans Price
  Click "Buy Now" to Purchase Full Plans
                 Postage Worldwide
We do not offer CNC cut files for this design.

The construction is epoxy-fiberglass-plywood composite, a stitch and glue composite system designed for efficient and fast building. To put it another way, the hull material is engineered as a fiberglass laminate whereby the plywood is treated as a thick, yet weaker laminate within the fibreglass schedule.
Building the boat is easy. The builder simply assembles the hull as a plywood boat first, then glasses the outside and inside with fiberglass, to produce a strong composite hull without all the time consuming woodwork associated with traditional plywood on frame. Bog, fair, paint then time for the internals. Its that easy
                         To see more on our  plywood composite construction method, please click HERE.    


SAVE TWO THIRDS! YES, you can build your own boat & SAVE TWO THIRDS of the cost of a factory built power or sailboat, YOU can prove it ... Just order the PLANS of your choice,  build your own & you can SAVE 50% of the cost of a USED boat &, you do not even have to do all the work yourself to save.

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 fabric - 24 sq.m ( 29 sq.yards)
1 kg (2.2 lbs) glue powder (Cabosil)
1kg  (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.  

                       With the best technical support: we will help you succeed!
                               All our plans come with full technical support.


We will respond immediately. At the same please visit our forum site, to share ideas about our boats and thousands of pictures - see completed boats and many of the building steps done by builders like you.
Also, all the fiberglass supplies required to build our boats are available at Bowdidge marine Designs, delivered to your door.

Designed Boat Plans

Proudly Australian
Marine Designs
 Boat Designs with "Reel Flare"

         We have boat plans (both yacht designs, catamaran designs and power designs) for all sizes for the amateur boat builder and Professional boatbuilder. From the 12ft Mushulu plywood stitch & glue power boat design to the Oceansky 57 strip plank composite multihull design. We design and build, plywood boats, strip plank boats and fibreglass composite boats to very modern styling for both yacht designs, multihull designs and power boat in round bilge, multi-chine or radius chine hull forms, including aluminum drift boats, aluminum landing craft, aluminum monohull boats, aluminum catamarans, aluminum special purpose boats, and aluminum RIBs

    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.

The Magnum 12 stitch and glue plywood car-topper 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.

With a borrowed 15hp 2 stroke Yamaha on the back, she hit a top speed of 24.8 knots. I must admit it was a little bit skittish at that speed and I wouldn't want to sustain that speed for long periods. With another person onboard she was very controlled even at full throttle when she reached 21.5 knots. With 4 adults and a 2 year old we still managed 19.5 knots! Slides a bit in fast turns but that is to be expected from a fairly flat bottomed hull, throttling back a little is all that is needed.
Casting deck is a success! I can safely stand anywhere on the forward deck! People were embarking from the shore straight up onto the bow. My sister's kids loved it!
Thanks again to Mark Bowdidge for the help and priceless advice throughout the build and thanks to all who have shared their builds and contributed to this archive of information.