The Canoe-maran

[ouchmytoe]

Hey everyone, I am a newbie here and have been dreaming up a project that is beyond my VERY limited experience. I inherited two, heavy fiberglass canoes that my father purchased at Costco. To accommodate my family of 7, I linked them to create a makeshift multi-hull boat. (Here's a photo of my boat(s) at Utah Lake at the Pleasant Grove Marina.)

I was a fun project but super heavy. I'd like to design–build two lightweight canoes that can be used alone or linked together in the best way possible for this situation. In addition, I'd love to add a sailing rig to the canoe-meran. So, what's the best canoe hull shape to accomplish this compromise? It will almost exclusively be used on Utah lakes and reservoirs so there's no need to accommodate the usual currents, chop, and waves common in a seaway. Any thoughts?

 

[portacruise]

The lowest weight canoes I'm aware of are inflatable- pack-in 2 man kayak/canoes. They could be strapped together as you have done with some challenging improvisation. Generally the best shape resembles what you already have, long and pointed at both ends. If it has to be solid, carbon fiber CF is probably the lowest weight material, but kind of pricey, even if you build it yourself. A couple of used CF sculling boats might also work, if you can find them cheap; but then the weight would go back up compared to inflatable. Don't you have 7 people to help carry what you have to the water?

 

[Robert Biegler]

I think you have several choices, depending on how you switch between different modes:
1) Something like what you have now, hulls wide enough to be used separately, only lighter.
2) Narrow hulls, still open and just wide enough to sit inside. Tie together as a catamaran, like here: Sea-Scouts Double Wa'apa https://outriggersailingcanoes.blogspot.com/2023/12/sea-scouts-double-waapa.html, or stabilise with much smaller outrigger hulls when used separately
3) If you want to adjust for payload, but you don't need two separate boats, then a modular boat, with a middle part that you can remove. That could be a catamaran, or a monohull. Catamaran would be easier for sailing. If this appeals to you, then you can save a lot of building: Expandacraft | Modular Boats and Outriggers https://expandacraft.com/

 

[Skip Johnson]

For build it yourself a foamcore stripper would work well, a comparable sized canoe should weigh about half as much. If you're building more than one just one form's required.

 

[portacruise]

One consideration when connecting 2 canoes to make a pontoon, is that the forces will usually not be the identical of the 2 hulls. One hull might experience a force upward with wind or waves, through a lever arm ending @ the connector, while the other might have a force downward. So that causes a torsion twist and possibly other stresses to the connector which might eventually cause a fatigue and failure. So it may be a good idea to check if anything is loosening or cracking on the connector, and re-tighten or replace periodically. Some designs use lashed hulls with some "give" flexibility to help with the twisting forces or a very strong heavy frame that can resist fatigue.

 

[Will Gilmore]

There's the pirogue.

Plans are easy to find online:
Pirogue https://www.lsuagcenter.com/portals/our_offices/departments/biological-ag-engineering/extension/building_plans/recreation/equipment/pirogue
Build two of these out of 3/16th plywood and add the 'iako to hold them together.

Consider cutting off a foot or so of the back to add a transom (flat back) for a small outboard. If you do it right, one person can carry each hull and the 'iako from truck to shore in three trips and assemble.

-Will