Masks, snorkels and fins
0 of 3 hands-on
01 Introduction
These three items are the most personal part of a kit. A mask that leaks or fins that hurt can spoil every dive, and good ones make a real difference. This lesson covers how they work and how to choose and care for them.
Objectives
- Explain why a mask needs an air space and what makes one fit well
- Describe the choices in snorkels and in fins, and how fin type affects movement
- Describe how to prepare, fit and look after a mask and fins
02 Watch
Seeing and moving
4 min · Video in production
- 1
An animation of light entering the eye through water, blurred, and then through an air space in a mask, sharp.
- 2
A diver testing a mask on their face without the strap, breathing in gently through the nose, and the mask staying in place.
- 3
Side-by-side fins: a full-foot paddle, an open-heel paddle and a split fin, with a diver kicking in each.
- 4
A diver rinsing a mask and fins in fresh water after a dive.
03 Learn
Why a mask needs an air space
The human eye is made to focus in air. In direct contact with water, the image is blurred. A mask holds a layer of air in front of the eyes so they can focus again. The mask has a glass front, a soft silicone skirt that seals to the face and a strap that holds it in place. Because the glass is flat, things look larger and closer than they are, by about a third.
Choosing a mask
- Tempered glass lenses are strong and resist scratching better than plastic.
- A low-volume mask sits closer to the face. It is easier to clear and gives a wider view, and it is usually preferred.
- A silicone skirt in a dark colour reduces glare and distraction, and a clear skirt lets in more light.
- The mask must fit your face. Try several, because shapes differ a lot.
- Divers who need vision correction can use prescription lenses or bonded-in corrective lenses.
- 1.Hold the mask against your face without the strap and breathe in gently through your nose.
- 2.If it sticks to your face without leaks, the seal is good.
- 3.Check that your nose can be reached, so that you can equalise your ears.
- 4.Fit the strap high on the back of the head, over the crown, not on the neck, and keep it snug but not tight.
Snorkels
A snorkel lets you breathe at the surface without lifting your head or using your cylinder gas. Simple J-shaped or flexible models are common. Some have a purge valve at the bottom to make clearing easier. When you are diving, a snorkel is often removed and stowed so that it does not catch or distract, and many divers choose not to carry one at all.
Fins
Fins increase the surface area of your feet, so each kick pushes more water. Fins come in several types.
| Type | Features | Typical use |
|---|---|---|
| Full-foot | A soft foot pocket worn on a bare foot, and no strap | Warm water, snorkelling, and travel |
| Open-heel | A larger foot pocket worn with a boot, and an adjustable strap | Cold water, shore diving with boots, and most scuba |
| Paddle blade | A flat or lightly shaped blade | General use, strong and easy to control |
| Split fin | A blade split down the middle | Some divers find them easier on the legs, though they may be less suited to some finning styles |
| Short, stiff blades | Fast, precise movement | Close work and tight spaces |
| Long, flexible blades | Gentle, efficient thrust | Relaxed open-water swimming |
A fin that is too stiff can tire the legs and cause cramp. One that is too soft may not give enough thrust. Fit matters as much as style: a good fin feels snug without rubbing, and does not slip off the foot.
Predict first
A diver's feet hurt and the fins keep slipping. What is the most likely reason?
Looking after them
- Rinse masks, snorkels and fins in fresh water after diving.
- Store a mask in a case so that the skirt does not distort or the lens scratch.
- Keep rubber and silicone out of strong sunlight and away from heat, which makes them brittle.
- Check straps and buckles before each trip, and carry a spare strap.
04 Explore
Try it yourself
Match each item with its purpose.
Match each item with its purpose.
- Mask air space
- Tempered glass lens
- Low-volume mask
- Open-heel fin
- Snorkel
05 Apply
Scenario
A new diver buys a mask because it looks good. At the dive site it leaks around the nose and keeps flooding. The diver keeps tightening the strap until it hurts.
What is the best advice?
06 Check
07 Summary
Key points
- A mask holds an air space so the eyes can focus. Fit is tested without the strap.
- Low-volume masks with tempered glass are a good choice for most divers.
- Snorkels help at the surface. Fins differ in foot pocket, blade shape and stiffness.
- Rinse and store them well, and carry spare straps.
Before you apply this in the water
- Have I been trained by a qualified instructor for this?
- Am I medically fit to dive?
- Do I have a buddy and a plan?
- Am I diving within my training and limits?
Answer every question in the Check section to mark this lesson complete.