Lorimer 445 Base Hull

The Lorimer 445 Base Hull is the foundation of a variety of creative one-off boat ideas. She'll make an excellent mother-son (or father-daughter, etc.) project.

This is a boat that's easy enough for a 10- to 15-year-old to build with a fair bit of help from Mom or Grandpa. It's durable enough to last until that 10-year-old is done with university, and versatile enough to grow and change roles as kids get older.

The base hull, shown below, is built using the taped-seam plywood technique. Lorimers are built in two parts. You start with the base hull, which includes the bulkheads, running surface, lower stem and engine mount. Then, after flipping her right-side-up, you add topside frame extensions and hull sides in whatever style you like.

The running surface is a fairly conventional 12° V-hull that will give stable, predictable performance at all speeds. As a kids' boat, she'd do well with an 8 or 10 hp outboard, perhaps getting an upgrade to 20 hp as the kids grow and the boat sees more "serious" use.

Her engine is set inboard in a well, keeping the motor and prop clear of fishing lines and safe from backing-into-the-dock accidents. The hull extensions aft of the engine provide extra buoyancy and extra planing lift in the stern where it's most needed. With a waterline beam of 1.8 m (6 ft), she's extremely stable for her size.

You don't need to spend a fortune on a boat like this. Three sheets of 12 mm (1/2") plywood and four sheets of 9 mm (3/8") plywood make up the bulk of the base structure. You'll also need about 90 m (100 yd) of fibreglass tape, 20 m2 (24 yd2) of fibreglass cloth, and a few buckets of epoxy to glue it all up with. To that, you can add a stack of dimensional lumber to build the topsides and whatever deck and interior suits your fancy.

What kind of topsides could you put on her?

How about a tugboat style? The wheelhouse provides excellent shelter for cold conditions. Smooth, rounded gunwales and a towing bollard ahead of the engine mean that she really can tow!

If you're the whimsical one on your cottage lake, why not build your Lorimer as a square-rigged galleon? Imagine the fun you'll have playing Pirates of the Muskokas in this thing! There's even room to mount a water cannon or two. No, she won't point to windward under sail, but that's what the 10-horse outboard is for.

Plans for the base hull are available now, and separate plans for the tug, galleon and more topside options are coming soon. Creative builders are of course welcome to come up with their own topside style to go with the Lorimer base hull.

Do note that the base hull alone is not a complete boat; topsides are required for seaworthiness.

Download page one of the plans here to start sketching your own ideas for the Lorimer. (You can turn off the "annotations" layer in the PDF if you want to print out a few for sketching.)

Length overall: 

4 m

Length waterline: 

4 m

Displacement light-ship: 

140 kg

Beam overall: 

2 m

Beam waterline: 

2 m

Wetted surface: 

4 m²

Power typical: 

8 kW

Power description: 

Single outboard 6 to 15 kW (8 to 20 hp)

Plans available: 


Plans cost: 

$50 CAD

Build status: 

Not yet built.

Design number: