Abstract
The dry snorkel is a critical breathing apparatus for snorkeling and scuba diving activities. Its core design lies in a buoyancy driven automatic valve mechanism that instantly seals the air inlet when the tube is submerged, preventing seawater ingress. Starting from the classification system of snorkels, this paper systematically elaborates on the working principle, core structural design, material selection and manufacturing processes, ergonomic and fluid dynamic optimization, as well as quality testing standards for dry snorkels, aiming to provide a technical reference for the design and manufacture of dry snorkels.
Keywords: dry snorkel; float valve mechanism; sealing design; injection molding; ergonomics
1. Introduction
A snorkel is a fundamental component of snorkeling equipment, allowing the user to breathe while the face is submerged. Together with the mask and fins, the snorkel is known as the “three essentials of diving” and forms the basic lightweight equipment for snorkeling activities. Based on differences in water proofing performance, snorkels are mainly divided into three types: wet, semi dry, and fully dry. Among these, the fully dry (dry) snorkel represents the highest level of water proofing technology in this field—by incorporating a float controlled water shutoff valve above the tube, the valve automatically closes upon submersion, almost completely preventing water from entering the tube.
The design of dry snorkels involves multiple technical fields such as fluid mechanics, materials science, and precision mechanical manufacturing. The quality of its design and technology directly affects the user’s safety and comfort. This paper systematically discusses the design and technology of dry snorkels from the perspectives of working principle, structural design, material processes, and quality control.
2. Classification of Snorkels and Positioning of Dry Snorkels
2.1 Technical characteristics of the three types
Wet snorkels have the simplest structure, consisting only of a tube and a mouthpiece, with no water proofing device. Their advantages are a simple structure and low cost, but the drawback is that once the tube is submerged, seawater flows directly into the tube, and the user must expel the water through forceful exhalation.
Semi dry snorkels are equipped with a one way valve at the front end of the mouthpiece, and the top of the tube is usually fitted with a splash proof device. This design prevents surface splashes from entering the tube, but it cannot prevent water ingress when the tube is fully submerged.
Fully dry snorkels add an automatic float controlled valve above the tube, which closes automatically upon submersion. This technological breakthrough has brought a qualitative leap in the safety of snorkel use.
2.2 Performance advantages of dry snorkels
The core value of a dry snorkel lies in its active defense mechanism. When the top of the snorkel is submerged, the float valve rises under the buoyancy of water and seals the air inlet; when the tube re emerges above the surface, the float valve turns down under gravity and re opens the air passage. This process is completely automatic and requires no action from the user, effectively avoiding the risk of choking. Some products claim a water proofing success rate of over 95% in static or vertical submersion tests.
3. Working Principle and Core Structural Design of Dry Snorkels
3.1 Mechanical principle of the float valve mechanism
The core mechanism of a dry snorkel is the float valve, which operates based on Archimedes’ principle of buoyancy. A typical dry top head structure includes the head body, valve body, and float. The head body contains an air port communicating with the breathing tube, with the port opening located at the top of the head body. The valve body is pivotally connected between the head body and the float. When the float is submerged, it is driven by buoyancy to close the air port; when the float emerges, gravity causes the valve to open the port.
The key to this mechanical design is balancing the float’s buoyancy and gravity. The float density must be lower than that of water to ensure sufficient upward force underwater, while its weight must be enough to reliably return under gravity above the surface. In addition, the motion trajectory of the valve—including the pivot position and the length and angle of connecting links—directly affects the response speed and sealing reliability of valve closure and opening.
3.2 Valve sealing structure design
Sealing performance is the most critical technical indicator of dry snorkels. To achieve reliable water tight sealing, dry snorkels typically use a combination of soft sealing elements and rigid valve bodies. In a typical design, a soft rubber sealing ring is installed at the upper end of the snorkel tube, with an air inlet on the sealing ring that communicates with the tube. When the float valve closes, the valve body presses tightly against the sealing ring to form an airtight seal.
More advanced designs employ a taper sealing principle: the front float pushes against a silicone sealing ring under buoyancy, creating a taper seal. The advantage of taper sealing is that the greater the water pressure, the greater the compression force on the seal, thereby enhancing the sealing effect—this is a typical “self energizing” sealing design. A silicone sealing ring between the transparent top cover and the float valve housing further enhances overall sealing reliability.
3.3 Wave proof head and splash guard system
In addition to the float valve mechanism, dry snorkels are usually fitted with a wave proof head or splash guard system at the top of the tube to cope with surface splashes. The wave proof head contains a hollow sealed air chamber with grooves at the bottom of the partition, which not only keeps the wave proof head upright on the sea surface but also facilitates smooth drainage of any water that has entered the tube.
Some high end products adopt a multi layer curved splash guard system, further improving drying efficiency through successive barriers. This design effectively reduces the amount of splash water entering the tube during the transitional state before the float valve is fully closed.
4. Material Selection and Manufacturing Processes
4.1 Tube materials
The upper part of the snorkel (the tube) is generally made of semi rigid plastics, such as PVC, PP, or PE. These materials offer good formability, sufficient structural strength, and moderate cost, meeting the requirements for rigidity, impact resistance, and seawater corrosion resistance in underwater environments.
The inner diameter of the tube is usually about 2 cm, with a length generally between 30 and 35 cm. When the tube length exceeds 40 cm, the lungs cannot effectively overcome water pressure during inhalation, and exhaled carbon dioxide tends to accumulate in the tube, reducing ventilation efficiency and possibly leading to hypercapnia. Therefore, the geometric dimensions of the tube are the result of comprehensive considerations of fluid mechanics and human physiology.
4.2 Mouthpiece and sealing material
The mouthpiece is the part that directly contacts the human body, and its material selection directly affects comfort and safety. High quality mouthpieces are mostly made of food grade silicone, which is non toxic, odorless, hypoallergenic, soft, and comfortable. Silicone also exhibits good biocompatibility and aging resistance, maintaining stable physical properties over long term exposure to seawater and sunlight.
Seals (such as sealing rings and gaskets) are also made of silicone. The elasticity and flexibility of silicone enable reliable airtight cooperation with rigid valve bodies, while its hydrolysis resistance ensures long term sealing performance under prolonged seawater immersion.
Some high end products use liquid silicone rubber (LSR) through precision cold runner injection molding to achieve higher dimensional accuracy and better surface quality.
4.3 Injection molding process
The manufacturing of various components of dry snorkels mainly uses injection molding. Injection molding is a process in which thermoplastic or thermosetting materials are heated and melted, then injected into a mold cavity, and cooled and solidified to obtain molded products.
For larger parts such as the snorkel tube, single shot injection molding is typically used, producing a complete tube body in one step. This process offers high production efficiency, good dimensional accuracy, and suitability for mass production. For complex functional components (such as the float valve assembly and top head), multi component or insert injection molding may be employed to combine different materials (e.g., rigid plastic framework and soft silicone seal) in a single molding operation.
In addition to injection molding, some flexible components (such as corrugated tube sections and bellows) may be produced by extrusion or blow molding.
4.4 Assembly process
A dry snorkel is assembled from multiple independent components, including the tube, top head (with float valve mechanism), mouthpiece, and retaining clip. The core of the assembly process is to ensure air tightness and mechanical reliability at each connection.
The connection between the top head and the tube typically uses snap fit or threaded structures with sealing rings to achieve airtight joints. The mouthpiece is usually connected to the tube by interference fit or slot fixation. The retaining clip secures the snorkel to the mask strap and is often designed to be rotatable so that users can adjust the snorkel angle according to personal preference.
Notably, some designs integrally mold the waterproof components with the tube in one shot, reducing assembly steps and thereby lowering manufacturing costs while minimizing potential leak points.
5. Ergonomic and Fluid Dynamic Optimization
5.1 Tube profile design
The tube shape design of a dry snorkel not only concerns functionality but also directly affects the user’s comfort and efficiency while moving in water. A fluid dynamically optimized tube shape effectively reduces water resistance, allowing the user to swim faster with less energy expenditure.
An excellent tube design typically adopts an airfoil shaped cross section, with the pointed edge oriented in the direction of motion to effectively reduce turbulence and drag. The bending curvature of the tube must match the contour of the human face, and J shaped or L shaped bends are commonly used. A design that closely follows the head profile eliminates gaps between the tube and the head, thereby reducing turbulence generation.
Some high end products feature a 3D curved tube design, providing the optimal breathing angle through precise calculation of the tube’s three dimensional curvature. A low profile, streamlined and gradually tapered tube further reduces water resistance.
5.2 Ergonomic mouthpiece design
The ergonomic design of the mouthpiece directly affects the user’s comfort and duration of use. A well designed mouthpiece should conform to the user’s dental arch shape, distribute biting pressure evenly, avoid chafing oral tissues, and not cause jaw fatigue.
Advanced mouthpiece designs use contoured shapes to fit different dental arches. The mouthpiece body typically includes tooth grooves for biting and fixation, as well as curved pads to ensure a tight seal around the mouth. Some designs also feature a concave arched top to accommodate the tongue’s resting position during diving, further enhancing comfort.
5.3 Drainage system design
Even the most advanced dry snorkels may admit a small amount of water due to float valve response delays or incomplete sealing in actual use. Therefore, an efficient drainage system is an important part of dry snorkel design.
The drain valve is usually located at the lowest point of the snorkel (i.e., near the mouthpiece) and uses gravity to expel accumulated water. Specially angled high flow drain valves can discharge water during each breathing cycle, keeping the breathing chamber dry. Some designs employ dual drain valves to further improve drainage efficiency. The bubbles discharged by the drain valve should not obstruct the user’s vision, which is also a factor to consider in drainage system design.
6. Quality Testing and Standards
6.1 Standards system
As diving equipment involving personal safety, the quality of dry snorkels must meet corresponding standards. Internationally, snorkels are required to comply with standards such as BS EN 1972 2015 and ISO 18562 series. The current national standard in China is GB/T 35370 2017 Testing methods for diving respirators, proposed by the National Technical Committee on Diving Equipment of Standardization Administration of China (SAC/TC306).
6.2 Core testing items
Quality testing of dry snorkels covers multiple aspects:
Airflow resistance test: Measures the airflow resistance during breathing to ensure smooth respiration. Excessive resistance increases breathing effort and may lead to fatigue or panic.
Sealing performance test: Using underwater air tight pressurization methods, the snorkel is placed at a specific depth to check for leaks at connections and the float valve mechanism.
Material safety testing: Verifies that the snorkel material is non toxic, non irritating, and safe for human contact.
Durability and environmental adaptability tests: Includes abrasion resistance, UV resistance, material aging resistance, and environmental temperature adaptability. Since snorkels are long term exposed to harsh conditions such as seawater and sunlight, material durability is directly related to product lifespan and safety.
Snorkel flex fatigue test: Simulates repeated use to verify the structural integrity of the tube.
7. Conclusion
The design and technology of dry snorkels constitute a comprehensive technical field integrating fluid mechanics, materials science, precision manufacturing, and human factors engineering. From the mechanical principles of the float valve mechanism to the engineering implementation of taper seals, from fluid dynamic optimization of the tube to ergonomic mouthpiece design, every aspect reflects a deep integration of engineering technology and user experience.
With continuous advances in materials science and manufacturing processes, dry snorkels are moving toward lighter weight, more efficient sealing, lower breathing resistance, and better ergonomics. In the future, the introduction of intelligent sensors, the application of new sealing materials, and more precise manufacturing techniques are expected to further enhance the performance and reliability of dry snorkels, providing diving enthusiasts with a safer and more comfortable underwater breathing experience.
WAVE China is a diving snorkels manufacturer. If you are interested in diving snorkels, please contact us.
