Why Aluminum and not Carbon Fiber Iatos?

Right from Day One, we have used aluminum iatos for our outrigger canoes. Many people have wondered why. Today, we are going to explain.
Iatos are booms that attach the outrigger to the canoe. Each canoe has two iatos that hold the outrigger in place. Aluminum iatos are tubular piece made from straight pipes that are bent.

What’s the difference between aluminum and carbon?

The diagram below shows the deformation of a material (in %) as a function of force applied to it (measured in Newtons).

We observe three characteristics :

- Elasticity is reversible deformation, i.e. up to a given effort, the piece returns to its original form. Carbon’s elasticity is very high because it can resist very great efforts with deformation. However, aluminum’s elastic deformation is lower because it deforms sooner than carbon.
- Plasticity is the area where the applied force causes irreversible deformation. Aluminum is a material that can undergo deformations while carbon breaks.
- Fracture is the point where we observe a break in the material.
In summary, carbon fiber composites are very resistant but almost non-deformable materials, therefore breakable. Aluminum, however, is not very resistant but is deformable.
We can compare the behavior of aluminum with that of a fork while carbon behaves like a pencil.

So, why did we choose aluminum?

Let's say you set out to sea for a downwind. Your carbon fiber iatos are worn and old. You get hit by a side swell and your outrigger canoe flips. As your outrigger turns over, your iatos break. You find yourself at sea with no iatos and unable to flip over your boat. As carbon wears over time, micro defects are created that are not visible to the naked eye. This means that you can’t anticipate changes in your Iatos. This wouldn’t happen if you have aluminum iatos. Since aluminum iatos are "deformable”, wear can be seen directly on the tubes : folds, bulges, etc. By observing the deformation during a session, you can get back to shore without danger. Once you reach land, you simply change them. So, we preferred to focus on safety by choosing aluminum iatos that are as light as carbon to avoid any loss of performance.