As sailors, we spend long hours exposed to reflected glare from water, wind that strips our skin barrier, salt that dehydrates, and UV radiation that never truly takes a day off. And here’s the first myth to dispel: UVA rays are just as present in January as in July.
Sunscreen is not a summer beach-day accessory. It’s a year-round discipline, just as important as your lifejacket.
Skin Cancer Is Common but Preventable
Skin cancer is the most prevalent form of cancer worldwide. There are more diagnosed cases than all other cancers combined. The good news? It’s also one of the most preventable.
A few sobering facts:
- Just one severe sunburn before age 16 doubles the risk of melanoma.
- Daily sunscreen use significantly reduces the risk of skin cancer and premature aging.
- UV damage is cumulative. Every unprotected day adds up.
For sailors, “avoid the sun between 10am-4pm” is not realistic. Racing, deliveries, cruising and offshore passages happen 24/7, and most definitely when UV is strongest. That means protection strategy becomes critical.
Understanding UV: UVA vs UVB
Ultraviolet radiation reaching Earth consists mainly of two types:
UVA – The Ageing Ray
- Accounts for ~95% of UV radiation reaching Earth
- Present all day, all year
- Penetrates clouds and glass
- Reaches deeper skin layers
- Contributes to DNA damage and skin cancer
- Breaks down collagen and elastin
UVB – The Burning Ray
- Causes visible sunburn
- Peaks midday and in summer
- Damages surface skin cells
- Strongly linked to skin cancer
SPF only measures UVB protection. That means you must choose a broad-spectrum sunscreen to ensure UVA protection.
What SPF Really Means
Consumers are often misled by very high SPF numbers. Here’s the reality:
- SPF 15 blocks ~93% of UVB
- SPF 30 blocks ~97%
- SPF 50 blocks ~98%
- SPF 100 blocks ~99%
That jump from 30 to 100 is only about 2% more protection – not double.
Imagine 100 UV rays hitting your skin:
- SPF 30 allows about 3 through
- SPF 50 allows about 2
There is no sunscreen that blocks 100% of UV.
For most sailors, SPF 30-50 broad-spectrum applied correctly and reapplied frequently is more important than chasing ultra-high numbers.
And remember:
- You need about 30mL (a shot glass full) for full adult body coverage.
- Reapply every 2 hours, and after swimming (or spending some time on the bow), sweating or towel drying.
- “Water-resistant 80 minutes” does not mean all-day protection.
The FDA no longer allows the terms “waterproof” or “sweatproof”, because they were misleading.
Sailors Need Extra Strategy for the Environmental Conditions at Sea
Heat increases sweat and oil production, breaks down sunscreen faster, and reduces the stability of chemical filters. Humidity weakens film adhesion on the skin, causes patchy coverage, and makes more frequent reapplication necessary. Wind adds another layer of stress through abrasion from salt and sand, accelerates evaporation, and can cause wind burn, which is often mistaken for sunburn. Wind burn occurs when wind strips away the skin’s natural oils and weakens its protective barrier. When combined with UV exposure, it intensifies redness, stinging, and dehydration. For offshore sailors, this is a daily reality.
Mineral vs Chemical Sunscreen. What’s the Difference?
There are two main categories on the market.
Chemical Sunscreens
These absorb UV radiation and convert it into heat.
Common ingredients include:
- Oxybenzone
- Octinoxate
- Octocrylene
- Avobenzone
- Homosalate
Concerns:
- Can degrade in sunlight
- Linked in independent studies to hormone disruption
- Some enter the bloodstream
- Associated with coral reef damage
- Often contain preservatives, parabens, and synthetic additives
They dominate the market because they:
- Are cheaper
- Apply clear
- Leave no white cast
But cheaper for whom?
Mineral (Physical) Sunscreens
Mineral sunscreens use:
- Zinc Oxide
- Titanium Dioxide
These sit on top of the skin and reflect/scatter UV rays.
Why Zinc Oxide Matters
Zinc oxide is the only mineral providing strong protection across both UVA and UVB. It:
- Is photostable (doesn’t break down in sunlight)
- Does not generate harmful byproducts
- Is gentle on sensitive skin
- Is stable in salt water and chlorine
Nano vs Non-Nano
Particles under 100 nanometers are considered “nano.” There is insufficient long-term data on nanoparticle absorption into the bloodstream or impact on marine life. Following the precautionary principle: Choose non-nano zinc oxide. Always read both active and inactive ingredient lists. Harmful additives can hide in “inactive” sections.
Reef-Safe. What Does It Actually Mean?
Here’s the complication: “Reef-safe” is not a regulated term. Many products claim it while still containing harmful chemicals. The most referenced regulatory benchmark is Hawai‘i Act 104, which bans oxybenzone and octinoxate due to coral damage.
Ingredients Commonly Linked to Reef Harm:
- Any form of microplastic sphere or beads
- Oxybenzone
- Octinoxate
- 4-methylbenzylidene camphor
- Octocrylene
- Para-aminobenzoic acid (PABA)
- Methyl Paraben
- Ethyl Paraben
- Propyl Paraben
- Butyl Paraben
- Benzyl Paraben
- Triclosan
Why It Matters
Coral reefs:
- Cover less than 1% of the ocean floor
- Support over 1 million species
- Sustain ~25% of all marine life
Globally, an estimated 14 000 tons of sunscreen enter oceans annually.
Chemical UV filters can:
- Damage coral DNA
- Interfere with reproduction
- Increase bleaching susceptibility
- Accumulate in marine food webs
Coral bleaching is a stress response. If stress continues, reefs die. As sailors, this is not abstract. These are the ecosystems we sail over.
Best Practice for Sailors
Sunscreen is your second line of defence. Your first line should be:
- UV shirts / rash guards
- Wide-brim hats
- Sunglasses
- Neck buffs
- Shade when possible
Then apply sunscreen to exposed areas:
- Face
- Nose
- Ears
- Neck
- Hands
- Ankles
What to Look For:
- Broad-spectrum
- SPF 30-50
- Non-nano zinc oxide (primary active ingredient)
- 80-minute water resistance
- No oxybenzone, octinoxate, octocrylene
- No parabens or microplastics
Avoid:
- Spray sunscreens (inhalation risk + environmental drift)
- Fragrance-heavy formulas
- “Hypoallergenic” claims (not a regulated term)
- Chemical UV filters harmful to reefs and marine life
Independent resources like the Environmental Working Group’s Skin Deep database allow consumers to research ingredient safety.
Applying a Global Perspective
Australia experiences some of the strongest UV radiation in the world, with two in three Australians diagnosed with skin cancer by age 70. But this is not only an Australian concern. UV exposure accumulates globally, and sailors spend more time than most directly under its intensity.
Meanwhile, the oceans absorbing that sunlight are under strain. Coral reefs, including the Great Barrier Reef, face repeated bleaching and chemical stress. In northern waters, the Baltic Sea is battling oxygen depletion and algal blooms, making it one of the world’s most vulnerable seas. In semi-enclosed waters especially, pollutants linger. What we rinse off our skin does not vanish. It circulates, settles, and accumulates within marine ecosystems.
Choosing the right sunscreen is not just about personal protection. It is about protecting coral reefs, fragile seas, and the broader marine world we depend on.
The Final Foundation
- Protect your skin. It’s your largest organ.
- Protect the oceans. They are the largest life-support system we have.
- Wear protective clothing.
Apply broad-spectrum, non-nano mineral sunscreen.
Reapply often.
Read ingredient labels – not marketing claims. - We cannot control everything affecting our oceans.
But sunscreen is one habit entirely within our hands.
