Marine First Aid Essentials

When you're out at sea, you don't have the luxury of a nearby clinic, a fast ambulance, or mobile phone service that works 100 percent of the time. Whether you're days from shore or just off the coast, you need to be ready to handle medical issues on your own – because chances are, you are the first responder.

That’s where marine first aid comes in. It’s not about stocking every drug known to man. By packing smart and knowing how to handle some of the most common incidents, you can set yourself (and everyone else around you) up for a better and safer experience.

With this in mind, let’s walk through exactly what you should have onboard, how to use it, and how to respond to the most common medical situations at sea.

Start With a Properly Stocked Marine First Aid Kit

A basic travel first aid kit won’t cut it on a boat. Marine conditions – remote locations, movement, salt, heat, humidity – demand much more robust supplies. Your kit should be organised, waterproof, clearly labelled, and easily accessible in the event of an emergency.

Here’s what your marine first aid kit should include at a minimum:

Wound Care

• Sterile gauze (4x4s, 2x2s) and large trauma pads
• Assorted adhesive bandages
• Medical tape
• Alcohol wipes and antiseptic (povidone-iodine or chlorhexidine)
• Haemostatic agent (e.g., QuikClot)
• Elastic bandages (ACE wraps)
• Tourniquet (ideally windlass style)

Instruments & Tools

• Trauma shears
• Tweezers
• Digital thermometer
• Irrigation syringe (for flushing wounds)
• CPR face shield or mask
• Splints (SAM splints are ideal)
• Nitrile gloves (lots of them)
• Headlamp or flashlight

Medications

• Pain relievers: ibuprofen, paracetamol (also known as acetaminophen)
• Antihistamines: diphenhydramine (Benadryl) for allergic reactions
• Seasickness meds: meclizine, dimenhydrinate, or prescription scopolamine
• Antibiotic ointment
• Antidiarrheals: loperamide (Imodium)
• Antacids
• Hydrocortisone cream
• Oral rehydration salts
• Prescription meds for known crew conditions
• Emergency antibiotics (with medical guidance)

Specialty Supplies

• Epinephrine auto-injector (if anyone has a known severe allergy)
• Space blanket or thermal bivy sack
• Instant cold packs
• Burn dressing (like Water-Jel)
• Eye wash solution
• Suture or wound-closure strips (if trained)

As you build out your first aid kit, be sure to customise based on your trip length, distance from medical care, and crew size. If you're going offshore or international, your kit should be closer to what you'd find in a wilderness expedition bag.

The Basics of Onboard Medical Care

A well-stocked kit is only half the battle. You need to know how to use it – especially when you're the only one around to respond. Consider taking a Wilderness First Aid or Marine First Responder course, which prepares you for scenarios where help is hours (or days) away.

In the meantime, here’s how to handle some of the most common conditions at sea.

1. Hypothermia
   You might assume hypothermia only strikes in freezing temperatures or icy waters, but it’s more common and dangerous than you think. On the water, wind and wet clothing accelerate heat loss. Even water in the low 20°C range (70° F) can cause hypothermia if exposure is prolonged. It can happen during a man-overboard situation, after a storm drenches the crew, or even just from sitting wet in a breezy cockpit for too long.
   
   When you’re offshore or in a remote anchorage, your ability to recognise and respond to hypothermia quickly becomes critical. You’re trying to prevent a slide into more serious conditions, like confusion, unconsciousness, and potentially fatal heart problems.
   
   Your first job is to notice when something’s not right. Early-stage hypothermia often gets overlooked. Keep an eye out for things like shivering, clumsiness, mumbled or slurred speech, and excessive drowsiness.
   
   As hypothermia progresses, the body’s core temperature drops further. Ironically, one sign of worsening hypothermia is that the person may stop shivering altogether. They may start to feel sleepy or unresponsive. That’s when things get dangerous.
   
   If you suspect someone is hypothermic, act fast. Even if they’re still alert and able to talk, you want to reverse heat loss before it becomes critical. Here's what to do:

• Get them out of the wind and wet clothing. Even if you're not equipped with a full change of clothes, getting them into something dry – even wrapping them in a towel and foul weather gear – is better than leaving wet clothing on. If you have a dry blanket or sleeping bag, use it.
• Insulate and cover the core. Focus on the torso, neck, and head. If possible, put warm water bottles (not hot) in the armpits, on the chest, or between the thighs. Avoid applying heat to the arms or legs, which could actually make the situation worse by forcing cold blood back to the heart.
• Lay them flat. Don’t let them walk it off or move too much. Gentle handling is important. In severe hypothermia, sudden movement can trigger heart arrhythmias.
• Give warm fluids. Offer warm, sweet, non-alcoholic drinks. Avoid caffeine, which can accelerate heat loss. Never try to force fluids on someone who is drowsy or struggling to swallow.
  
  Be sure to use anything and everything you have. This may include pace blankets, dry towels, spare bedding, or even a dry sail. If the cabin is warm, get them below and close off the area to trap heat.

2. Allergic Reactions
   When you’re out at sea, far from emergency medical help, even a minor allergic reaction can escalate into a serious situation if you’re not prepared. Allergies don’t care whether you’re docked in a marina or anchored in a remote cove – and reactions can come on fast, especially with unknown triggers.
   
   You need to be ready to act quickly and confidently when someone on board starts showing symptoms of an allergic reaction, whether it’s a mild rash or full-blown anaphylaxis.
   
   Allergic reactions vary widely in severity. Some show up within minutes; others may take hours. Keep an eye out for the following:

• Itchy skin, hives, or rashes
• Sneezing or nasal congestion
• Mild swelling (especially around the face or lips)
• Difficulty breathing or wheezing
• Swelling of the throat or tongue
• Rapid or weak pulse
• Dizziness or fainting
• Sudden drop in blood pressure
  
  Anaphylaxis can become fatal within minutes, so if someone is showing signs of a severe reaction, you need to treat it as a medical emergency.
  
  If the person has a prescribed epinephrine auto-injector (such as an EpiPen), use it immediately. Don’t wait to see if symptoms worsen. Administer the shot into the outer thigh and hold it in place for 3 to 10 seconds, depending on the device instructions.
  
  If you have a VHF radio or mobile phone signal, call for medical assistance. If not, consider changing course toward the nearest port. Even if symptoms seem to subside, follow-up medical care is essential.
  
  Lay the person down flat and elevate their legs if they’re lightheaded (unless they’re having trouble breathing, in which case let them sit up). Don’t give food or drink during an active reaction and never leave them unattended.
  
  For non-life-threatening reactions like itching, rashes, or minor swelling, give an oral antihistamine such as diphenhydramine (Benadryl) or loratadine (Claritin). These can take 15 to 30 minutes to kick in, but they help relieve symptoms and prevent further escalation.

3. Dehydration and Heat Exhaustion
   When you’re out on the water, it’s easy to underestimate how quickly heat and sun can wear you down. The breeze masks sweat, and the glare reflects off the water. Before you realise it, your body may be overheating and running low on fluids.
   
   Dehydration and heat exhaustion are two of the most common medical issues at sea. Left unchecked, they can lead to poor decision-making, fainting, heat stroke, or even more serious complications. Thankfully, with a bit of awareness and preparation, you can avoid both.
   
   Dehydration doesn’t always hit you all at once. It builds gradually, especially in hot or windy conditions where you lose fluid through sweat and evaporation.
   
   Here’s what to look out for:

• Dry mouth or sticky saliva
• Headache or light-headedness
• Dark yellow urine (or low urine output)
• Muscle cramps
• Fatigue or sluggishness
• Irritability
  
  If someone on your crew seems slower to respond, is acting irritable, or has stopped sweating, assume dehydration is a factor and take action right away.
  
  If someone is overheating or dehydrated, start by getting them out of the heat. Move the person to a shaded, well-ventilated area. If you’re at anchor, get them on deck in the breeze or under a sunshade. If sailing, find any available shade. (Even a towel or bimini cover can help.)
  
  As they sit out of the heat, have them sip cool (not ice-cold) water slowly. Avoid chugging large quantities at once, especially if they’re nauseated. Oral rehydration salts (ORS) or electrolyte tabs can help restore balance faster than plain water.
  
  The next step is to use cool, wet towels or a damp t-shirt on the neck, armpits, and forehead. If safe, have the person lie down and elevate their legs. If the situation continues to deteriorate, consider a controlled dunk in the water (supervised) followed by air drying in the shade.

4. Seasickness
   Seasickness is something nobody wants to deal with. At its worst, it can completely debilitate you or a crew member. When you're offshore or in rolling swells, seasickness can last hours or even days, and it can impact your health and safety.
   
   The first step is to understand what seasickness is and how it’s caused. In the most basic sense, it’s a type of motion sickness caused by conflicting signals between what your eyes see and what your inner ear feels. On a boat, your inner ear detects movement – pitching, rolling, and yawing – but your eyes (especially if you’re looking down or inside) don’t always register the same motion. This mismatch confuses your brain, triggering symptoms like nausea, vomiting, dizziness, headache, and fatigue.
   
   What makes seasickness tricky is that some people are fine one day and sick the next, depending on sleep, hydration, stress levels, or sea conditions. That’s why the best approach is to be proactive. You want to prevent it before symptoms set in. Once nausea takes hold, it’s much harder to reverse.
   
   Here’s what works:

• Choose the right position. Stay topside in the fresh air, near the centre of the boat, where motion is least. Keep your gaze on the horizon – it gives your brain a stable reference point and helps resolve the sensory mismatch.
• Avoid triggers. Greasy food, alcohol, strong smells (like diesel or fish), and dehydration all increase your chances of getting sick. Avoid these before and during sailing.
• Keep your head and body steady. Use your core and legs to absorb the boat’s motion instead of stiffening up or sitting slouched. A stable, active posture helps your body sync with the movement.
• Get ahead of it with medication. If you know you’re prone to motion sickness, take preventive meds before setting sail. Scopolamine patches, meclizine, and promethazine are all good options. You can also use ginger chews or capsules for mild cases.
  
  Despite preventative efforts, it’s still possible that someone gets sick. If that happens, you’ll want to get them to fresh air as quickly as possible. (Staying down in a stuffy cabin without good visibility is the worst thing they can do.)
  
  Once in fresh air, get the individual to stabilise their head so that it’s still and level. This reduces inner ear stimulation and can improve things. And while they may not feel like drinking anything, giving them some liquids is helpful, as dehydration will make the symptoms of seasickness even worse.
  
  Finally, if they haven’t already taken anything – and if they’re alert and able to keep liquids down – offer meclizine or a ginger capsule. For severe cases, suppositories or patches may be necessary if vomiting continues.

Stay Safe and Enjoy the Water

At TheYachtMarket, we believe everyone should have the opportunity to enjoy the sea and sail in style. But in order to do that, you also have to account for safety on the water. This means being prepared with the right first aid kit, knowledge, and crew. So, take the time to properly vet your vessel and crew.