Retailers and Dive Operators get asked this question time and time again by customers who already have a 3mm steamer for surfing or a hard-wearing scuba suit from their resort course. They can’t see why they would need to spend any more money on another suit for their morning dive on the reef. We need to be able to give a good explanation of the thermal maths, breath-hold physiology, and the speargun loading involved.
Different sports, different thermal problems
A surfer spends most of their time on land between sessions, generating heat between times in the water. They feel cold for short periods of time between sessions. A scuba diver is fully immersed in the water at all times, but is covered in scuba and dive equipment. They wear an undersuit but are limited by the amount of time they can spend underwater by the amount of gas in their scuba tank. A spearfisher is fully immersed in the water for long periods of time and does not move around much. Much of the time they are lying or sitting on the bottom of the sea stalking fish. For long periods of time, spearfishers can spend four hours or more in the water and often wear no wetsuit at all.
There are a number of unique factors which result in spearfishers losing more heat than a number of other activities. A major factor for a number of activities is the movement of water against the diver’s skin, removing any heat which would otherwise be lost due to conduction. For a number of water activities, this factor is the major factor for heat loss from a diver in the water. However, for a spearfisher, still water actually removes more metabolic heat from the diver than moving water. So, a number of factors result in a spearfisher losing more heat than a number of other activities. These factors result in cold water affecting a diver’s breath-hold time before the diver starts to feel cold. Therefore, even though a diver may feel fine in cold water, they are actually losing valuable breath-hold time. This increased oxygen consumption is due to the increased shivering and vasoconstriction in the peripheral blood vessels.
Why open cell changes the equation
The interior of a spearfishing wetsuit is typically made of raw, uncalendered neoprene. This exposed cell structure is excellent for grip and a tight seal on the skin. Almost no flushing layer is required between the suit and body. 5mm of open-cell wetsuit material provides significantly more warmth than 7mm of lined wetsuit material for the same amount of bulk, and also provides significantly more stretch.
Handling, As customers are familiar with wearing lined wetsuits, there can be a few difficulties when wearing open cell wetsuits. The wetsuits are prone to tearing on rough surfaces and therefore need to be lubricated with diluted conditioner or a specialised soap solution before wear. Abrasion is also a major problem for open cell wetsuits.
Two-piece construction and what it solves
The typical spearfishing wetsuit is made up of a high-waisted long john style bottom (beavertail style) and a hooded top. In the torso area of the wetsuit, it is doubled up to provide the most amount of insulation to the core area of the body. The arms and legs of the wetsuit are of single thickness to allow for the greatest amount of flexibility and mobility. The beavertail style wetsuit also has a flap in the back of the pants that ties up between the legs of the diver to prevent the creation of a water channel that would otherwise be formed by a zip down the back of the wetsuit.
This type of diving suit is normally supplied without a back zip as there are no seams for the zip to go around. However such a suit can be split down the side to make a lighter weight version for summer diving. For example a pant and top combination can be worn with a rash vest top for warmer weather diving. The same top can then be worn with a heavier weight version of the pant for the colder months of the year.
The hood is not an accessory
Most spearfishing hoods are made to fit on top of a wetsuit. The hood will be made of thin neoprene on the back of the ears to keep them from getting wet. Also, the face seal of the spearfishing hood is smooth to equalise pressure in the ears of the diver. Scuba hoods are made for shallower dives and for warmer water. Therefore, they are made for heavier thermal loads. These hoods usually have a hard face seal. They are not as easily equalised by the diver as a smooth face seal spearfishing hood.
Loading pads, stretch and the reality of repeated shots
Worked into the chest of the spearfishing wetsuit is a reinforced chest pad, made from textured rubber or high-density neoprene. This pad prevents the butt of the band gun slipping into the chest and causing discomfort while reloading the gun. On many dives the band gun is reloaded many times and this pad prevents discomfort to the chest area. Divers who reload constantly are usually better served by spearfishing wetsuits built with a proper loading pad from the outset, rather than a general purpose suit that wears through at the sternum.
The stretch in the mid to upper end of spearfishing wetsuits is for freediving as well as for spearfishing. Every restriction in a diver’s chest will cost them in terms of lung volume and every restriction on their arms will cost them in terms of oxygen.
| Feature | Surfing suit | Scuba suit | Purpose-built spearfishing suit |
| Construction | One piece, back or chest zip | One piece, heavy zip | Two piece, zipless beavertail |
| Interior | Lined, quick to don | Lined, hard wearing | Open cell, sealed to skin |
| Hood | Optional, separate | Separate, thick | Integrated, thin at ears |
| Chest | Smooth or printed | Plain | Reinforced loading pad |
| Exterior finish | Bright, branded | Black or high visibility | Camouflage or matte |
| Design priority | Warmth per millimetre, stretch | Abrasion, ballast integration | Warmth per millimetre, stretch |
Camouflage, visibility and the safety trade-off
Most retail spearfishing suits feature camouflage patterns that allow divers to remain hidden while fishing. The best patterns for kelp covered reef areas feature a combination of browns and greens, while blue and grey patterns are best suited for blue water environments. Sandy bottom environments are often best suited with light coloured patterns.
The biggest danger of camouflage for a diver is the danger of being run over by a boat. Because of this danger, in many countries, a diver using a float must also use a flag. Many divers using scuba also wear brightly coloured fins, and some even add a brightly coloured accent to their hood.
What to recommend and why
A Special Purpose Wetsuit for Reef Spear Fishing is Better than a General Purpose Surfer Wetsuit for a Serious Diver.
- Thermal performance at lower thickness, which preserves mobility and reduces lead requirements.
- Reduced flushing, which is the dominant heat loss mechanism during repeated descents.
- Hardware that survives loading, rather than wearing through in a season.
- Modularity across a wider temperature range from one purchase.
Measuring up for your Open Cell Wetsuit, chest, waist, length and height are all required to get the best possible fit. Standard retail wetsuits are cut to a ‘one size fits all’ off the rack template, so don’t expect too much from your local retailer.
