It looks simple but there’s a lot going on behind it. It uses a CFD code at the back-end to generate a full set of polars for each profile that’s behind the results. The reason for showing this view, is that it gets to the bottom of the real problem – the whole flight envelope, not just one point of chord at speed. It shows the force limit (expressed in Kg rather than N) of a foil at a certain chord and surface area,defined by the point at which lift breaks down and therefore the performance envelope is exceeded. This allows for a view of the problem of “how hard can this foil be pushed at a certain speed”. The drag in such a view is quite revealing – it shows that most sections that utilise reasonable laminar flow have a very similar overall drag for a given surface area and speed. So it’s actually not very interesting. They all look very similar. Reduce the surface area and you lose drag is what it boils down to. Also, with typical simulations to generate polars, they are set-up for wind tunnels and not for water – so there’s no consideration of cavitation onset, nor the significantly different freestream turbulence and laminar flow model.

Chris calibrated his CFD code using sound tank test data gathered over the years from various sources. So off-the-shelf aero sim packages are usually highly misleading for hydrofoils unless you calibrate the models. They are generally wildly optimistic in the laminar flow stakes, indicating there’s a problem with the turbulence model. From that, Chris developed a set of NLF profiles to best match our flight envelope requirements.

Polars… sure, we can make them but they don’t show the on-water behaviour. It’s funny but the competition for deepest drag bucket always ends in a spin-out for the poor test bunny. Until Chris wrote this code and played with things like salinity and temperature, it was easy and tempting to just look at L/D and drag buckets. Chris designs his profiles starting with a NLF pressure distribution he cooked up over the years, and an inverse design method that uses a genetic algorithm to fit the CFD output panels to something manufacture-able.

Our fins look a bit different. That’s because we engineer them from scratch. We have our methods and ideas that we use as a basis for our designs. The reason? We got tired of the endless copy cycle that stifles innovation in our great sport. We’ve noticed some of the other brands appreciating our work by mimicry. Like a stick insect that looks like a stick, it can be a convincing approach. We also know what it takes to get it right..

Two designs can look nearly identical, but they have remarkably different on-water behavior and performance. Some reasons for this:

Outline: it’s the obvious thing in fin design, but not the most important on its own..

Profile: two profiles can look similar, be smoothly shaped and have the same maximum thickness point, and even have the “hollow” in the shape at the back like our designs have. But it doesn’t take much to change a great profile into a dud.

Machining and Finish: arguably the most important part of the process. A great design won’t be so great if it’s not machined to tight tolerances, and finished properly (unless you are winning the lucky dip prize). We’ve all sailed mass produced copies of popular shapes that whistle and spin out, and others which vary obviously in performance from fin to fin..

We decided to cover all of these bases and make a fin range with performance second to none. Delivering unrivaled consistency, superior material quality, and thoroughly engineered designs.