Sonic v2: Downwind SUP Fin for Maximum Agility and Speed

The art of downwinding takes lots of practice and skill. There’s a lot more variables to consider compared to flatwater paddling, but the rewards—surfing open water swell for miles—are well-worth the effort.

Of course, any accomplished downwind paddler understands you need the right equipment to nail a perfect run. Two of the main performance characteristics that downwind paddlers look for are speed and maneuverability—the hallmarks of our Sonic v2 paddle board fin.

Designed to further enhance the characteristics of your downwind SUP board, with the help of downwind maestro Bernd Roediger we have refined the Sonic from the original version. With a reduced cord and smaller surface area, it instantly increases the maneuverability of your board and allows paddlers to chase down swells while downwinding. This fin is also great for those who enjoy surfing their raceboards^^, as it significantly loosens up the tail to allow for quick change of direction.

To get the maximum performance and enjoyment out of this fin, you will need to be a confident downwind paddler who aims to ride swell, not just paddle hard.

^^ surfing your race board is one of the best ways to improve your board handling and ideal training for down winding.

You may also like to consider – Maliko v3: Downwind SUP Fin for Intermediate to Advanced Paddlers


Reduced Cord Concept

The Reduced Cord Concept (RCC) enables us to reduce the surface area of the fin size while maintaining tracking. At only 14.5 cm, the cord of the Sonic v2 is 15 mm narrower than the original Sonic. While downwinding, this helps to make it easier to carve and change direction. Having as shorter base also enables you to move the fin forward and back—further back for more tracking and further forward for better turning. 

9.8% Less Surface Area

Due to the narrower cord, we were able to reduce the overall surface area by 21cm² (9.8%), when compared to the original Sonic. The result is a more maneuverable and faster fin, and these changes make a big difference over the course of a 10km+ downwind run. 

Fresh New Artwork

The Sonic v2 also comes with a fresh new look—a distinctive aesthetic that will appeal to a wide-range of paddlers. We included more info and specs on each fin, making it easier for customers and retailers to identify the differences between the models. We are lucky to have added a graphic designer to our staff (Glenn), and you can expect to see gradual improvements across the collections as we become more unified and cohesive in our branding.

Arthur Arutkin paddling with a Sonic v2 SUP fin from Black Project


Best For:Maximum agility & speed in ocean, surf & downwind racing.
Suitable For:Expert to professional athletes.
Depth (cm/in)18 / 7.09
Area (cm3 / in²)193 / 29.9
Cord (cm / in)14.5 / 5.7
Fin Base (cm / in)16.5 / 6.5
Leading Edge (degrees)45°
Foil TypeSymmetrical
ConstructionLiteCore Technology
Weight (gr / oz)150 / 5.29
Warranty1 yr
USA Retail (Ex Tax)$175
Buy Now


The Sonic v2 is a downwind fin for more advanced paddlers, but also performs well in surf race conditions. 

Advanced and Professional Paddlers

More experienced paddlers will find the Sonic v2 significantly improves the performance of their downwind board. This smaller fin’s surfing-inspired curved outline with a narrow cord and thinner foil helps paddlers better ride and connect swells at speed. Paddlers who are very confident on their board and like to focus on riding swells, rather than just paddling hard, will get the most out of this style and size of fin.

Surf Racing

The Sonic v2 is also a great choice for surf racing (or simply surfing your raceboard), as it makes the tail loose and makes it easier to make rapid adjustments and changes in direction. Surfing a 12’6” or 14” race board is hard, so any help that you can get will make a big difference. 

Rivers, Shallow Water & Anti-Weed

Due to its shallow depth and curved outline, Sonic fins have always been popular in rivers with flow and in shallow water. These characteristics also mean that it is great for shedding weed, kelp and trash and hence the Sonic is our most effective anti-weed SUP fin.




Professional Paddlers10
Advanced Paddlers8
Intermediate Paddlers3
Buoy Turning10
Weedy Water10
Shallow Water10
Sonic v2 SUP fin from Black Project
Sonic v2 SUP fin from Black Project


Very Responsive
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I have both the Sonic and the Tiger fins for my RS and find the Sonic to be the go-to for open water and downwind, exactly as designed. The board just loosens up underfoot with the Sonic and steers better on the bumps or tide eddies. Given neutral feet and calm water, tracking with the Sonic is great. Fit and finish are Formula 1 level.
My Go-To Fin
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The Sonic has become my go-to fin this summer. Good speed and tracking in many different conditions and sheds weeds like no fin I’ve ever owned. I do a distance race almost every year on a tidal river where weeds are a real problem in one section; this was the first year I didn’t need to stop to clean off my fin. I picked up no weeds (and I won the race). If I only had to own one fin, this would be the one.

What we think about the Sonic v2

Pure surfing joy, whether on an ocean wind blown swell or in breaking waves, the Sonic was always good, but the changes Bernd and I made with the v2 have really propelled this design forward. There is nothing better than riding swells, far out to sea while surfing on the tail on a 14ft race board, the Sonic v2 instills utter confidence and helps increase speed and promotes rapid turns. In surf race conditions the surfing inspired design really helps increase control and enables you to stay closer to the power zone of the wave. In the winter, this is the fin I put in my board when I take my raceboard out in the north shore surf, this is the ultimate and most rewarding challenge.  

 — Chris Freeman, Black Project SUP Founder 


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