Patented folding mechanism

FoldingFins use a patented mechanism that folds the blade along its longitudinal axis — engineered for divers who travel.

This is the only design in its class that folds without weakening the propulsion surface. After more than ten years on the market, it remains uncopied. The engineering came out of six years of joint research with one of Poland's leading defence and marine technology institutions.

FoldingFins™ is a trademark of EXOTECH Sp. z o.o.

Six years of R&D with the Polish Naval Academy

FoldingFins were developed jointly with the Akademia Marynarki Wojennej im. Bohaterów Westerplatte (Polish Naval Academy of Heroes of Westerplatte), Gdynia — under project BIODIVE FIN, 2017–2022.

EXOTECH's contribution was led by Mariusz Szymański — co-founder and co-inventor of the patented folding mechanism.

The collaboration combined EXOTECH's product engineering with the Naval Academy's testing infrastructure — a dedicated water tunnel, a humanoid swimmer's-leg manipulator, and a research team of three core staff plus eight habilitated experts across biomimetics, underwater robotics, materials science and mechanical engineering. Reached Technology Readiness Level 9 — the highest classification, meaning the design is fully proven through successful real-mission use.

Three peer-reviewed studies

The methodology, the apparatus and the FoldingFins themselves were all published in peer-reviewed journals between 2020 and 2022.

Head-to-head benchmark vs the industry's bestsellers

In the 2022 MDPI study, FoldingFins were tested side-by-side against the Aqualung Express Fin and the Scubapro Jet Fin — measured in a swimming pool with professional swimmers, using high-speed image processing.

The Strouhal number is a dimensionless quantity that captures the efficiency of fin-like propulsion. Biology suggests an optimal range of 0.2–0.4 (Taylor, Nudds & Thomas, Nature, 2003). Inside that range, propulsion is energetically efficient. Outside it, you waste effort.

Source: Piskur (2022) Table 1. Six FoldingFins test cases across three prototypes (BW, B, W) × two swimmers were measured — all within the biological optimum range. The full table is in the open-access paper linked above.

In short: same optimal propulsion physics as the two industry benchmarks — in a fin that folds along its longitudinal axis.

State-funded R&D, independently verified

BIODIVE FIN is a matter of public record. The project was funded by the Polish National Centre for Research and Development (NCBiR) and co-financed by the European Regional Development Fund — and the closure was formally recognized by NCBiR on 15 April 2021.

Project number

POIR.01.01.01-00-0046/17

Smart Growth Programme 2014–2020

Total project value

4,901,177.15 PLN

~ €1.1M · qualified costs

EU contribution (EFRR)

3,600,912.79 PLN

European Regional Development Fund

Independent verification — these claims are not "trust us." They are verifiable in public records and on the parent company's mandatory POIR disclosure page:

• exotech.pl/biodive-fin — corporate POIR disclosure (parent company EXOTECH)
• NCBiR project completion confirmation (15 April 2021) — PDF
• gov.pl/web/ncbr — funding agency (National Centre for Research and Development)

Recognition

Industry recognition for the engineering and the category.

Material Engineering — Mono-Hytrel® Construction

FoldingFins® is built entirely from Hytrel® ECO B — a high-performance thermoplastic polyester elastomer engineered for demanding applications. No other dive fin on the market uses single-material construction at this level.

Why it matters:

• Fatigue resistance: Hytrel® withstands thousands of fold cycles without performance degradation. Conventional plastic fins would crack; rubber fins would lose propulsion.
• Cold-water continuity: Where multi-material fins suffer joint mismatch in cold water (rubber stiffens, plastic doesn't), Hytrel® maintains uniform flex from tropical to polar conditions.
• Up to 74% biomass content: The ECO B grade derives most of its weight from renewable bio-based feedstock, making FoldingFins® one of the few dive fins on the market with meaningful sustainability credentials. Hytrel® ECO B is manufactured at a facility powered by 100% renewable electricity.
• Single-feedstream recyclability: No glue joints, no composite layers, no dissimilar materials. End-of-life FF can be reground and reused, unlike multi-material fins destined for landfill.