Cargo canoe to trimaran

Hello
Basic concept is to turn my 16' square stern cargo canoe into a motored platform. Looking for ideas on how to build two outrigger akas and attach them to my pontoons. Pontoons: would have a 15' long 1/4" x 20" plywood spine with blunt nose stems for and aft to which I would adhere foam to make 6" wide x 20" high x 15' pontoons. Before beginning anything I want to explore various ways to make the attachment to between pontoon and aka (crossbeams). The canoe would be powered with a 6hp outboard and perhaps oars. Would appreciate ideas on the attachment part. Thanks Steve (69yrs)

 

I suggest you buy a used canoe identical to what you have and attach them by the cross beams. Cheaper, easier and faster.

 

2" x 2" cross beams work great but larger may be necessary.
Bicycle tire tubes make excellent lashings.
Just replace them every year due to UV degradation.

 

Amazon.com https://www.amazon.com/Spring-Creek-Manufacturing-Canoe-Lashing/dp/B08SR3THHD

A search will turn up lots of choices, as well as DIY with 2 or 3 hulls. Its done with clamps without drilling needed if they need to go back to originals. Studying these will give ideas, Expandacraft has complete kits for 2 or 3 hulls.

 

Galvanized water pipes and hose clamps will hold the two hulls together.

 

You want to convert your square stern canoe into a Tri?

Easiest way to do it from a materials and build time perspective is to find yourself an inexpensive beach cat, preferably a more modern one with straight beams and use the beach cats hulls and cross beams and rudders leaving your transom available for hanging a motor off of.

The only real challenge will be how to best attach the cross beams to your center canoe hull.

Simplistic way to do it would be to build some support structure into your center hull then place the beams across the top and lash them to your support structure.

Make everything adjustable so you can tweak and change the relationship of the crossbeam height and position fore and aft to the canoe hull if you don’t want to figure all that out before hand.

Search using the term “FrankenTri” for inspiration.

 

The amas can be much smaller for less water resistance, and still provide the needed stability.