How Do Life Jackets Work?
Navigating the world of life jackets, with their diverse range and functionalities, can be daunting.
Whether you’re a boat owner, water sports enthusiast, or beach vacationer, understanding these crucial safety devices is vital.
I’ll unpack the science behind life jackets, breaking down their buoyancy mechanisms, categories, and performance ratings.
Drawing from personal experience, I’ll convey the topic in clear, accessible information, empowering you to make informed safety decisions for your next water adventure.
At a Glance:
1️⃣ Life Jackets work by using buoynacy, discplacement, Archimedes principle, stability and floatation.2️⃣ Some can turn the wearer over and keep the mouth and nose out of the water, while others only provide essential buoyancy while the swimming survivor waits for rescue.
3️⃣ Two categories are used to score life jackets, Performance TYPE and Performance LEVEL life jackets.
🏊♂️ How Do Life Jackets Keep You Afloat?
A life jacket keeps you afloat by providing additional buoyancy. Here’s a concise explanation:
1️⃣ Buoyancy: Life jackets are filled with materials that are lighter than water, such as foam or gas. This makes the jacket less dense than the water.
2️⃣ Displacement: When you wear a life jacket and enter the water, the jacket displaces a volume of water that weighs more than the jacket itself.
3️⃣ Archimedes’ Principle: According to this principle, an object submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. Since the life jacket displaces water that weighs more than it does, it experiences an upward force.
4️⃣ Stability: The life jacket is designed to distribute this buoyant force evenly across your body, particularly around the chest and back, keeping you stable in the water.
5️⃣ Floatation: The upward force (buoyancy) counteracts the force of gravity pulling you down, allowing you to float.
There are a handful of form factors available for life jackets
Inherent Jackets
As the name implies, inherent Life jackets are “inherently buoyant.” They are filled with foam or similar material and are rated as follows:
| Size | Life jacket category | Buoyancy Rating |
|---|---|---|
| Adult | TYPE I | 22 lbs. |
| Adult | TYPE II and III | 15.5 lbs. |
| Adult | TYPE IV | 15.5 to 22 lbs. |
| Adult | LEVEL 70 | 15.75 lbs. |
| Youth | TYPE II and III | 11 lbs. |
| Youth | TYPE V | 11 to 15.5 lb. |
| Child | TYPE II | 7 lbs. |
| Infant | TYPE II | 7 lbs. |
Inflatable Jackets
A gas cartridge is activated, which fills the air compartments and makes the life jacket buoyant.
It’s important to remember that an inflatable jacket won’t work if the bladder has a tear in it.
Learning why regular and correct life jacket maintenance to ensure they work when you need them most is highly recommended.
Two kinds of inflatable jackets are available:
- Those that automatically inflate.
- Those that require manual inflation.
The capabilities of inflatable life jackets are listed below.
| Size | Life jacket category | Buoyancy Rating |
|---|---|---|
| Adult | TYPE I and II | 34 lbs. |
| Adult | TYPE III | 22.5 lbs. |
| Adult | TYPE IV | 22.5 to 34 lb. |
Hybrid Jackets
Hybrid life jackets combine the capabilities of the inherent (foam-filled) and inflatable life jackets.
| Size | Life jacket category | Buoyancy Rating | Wearers Size |
|---|---|---|---|
| Adult | TYPE I Land III | 10 lbs. | 22 lbs. |
| Adult | TYPE IV | 7.5 lbs. | 22 lbs. |
| Adult | LEVEL 70 | 9 lbs. | 15.74 lbs. |
| Youth | TYPE II and III | 9 lbs. | 15 lbs. |
| Youth | TYPE IV | 7.5 lbs. | 15 lbs. |
| Child | TYPE II | 7.5 lbs. | 12 lbs. |
| Infant | Not available for infants | N/A | N/A |
Special Purpose Jackets
These life jackets are constructed case-by-case, depending on the requirements.
🎽 Types Of Life Jackets
The available life jacket types are rated by the buoyancy specifications.
They are divided into two categories listed below.
⚖️ The Correct Weight Category Life Jacket Must Be Selected
The most appropriate life jacket must be chosen.
The weight categories of lifejackets are listed below. Don’t be confused by a lifejacket’s buoyancy capability being compared to the wearer’s weight.
The user’s weight that is indicated is on land and not in the water, where a human body has some natural buoyancy.
Adult Life Jacket
These life jackets are designed to keep the wearer who weighs more than 88 lbs. (40 kg) afloat.
Teenager Life Jacket
Youth Life Jackets are designed to keep the wearer who weighs between 55 lbs. and 88 lbs. (25 – 40kg) afloat.
Young Person Life Jacket
Young Person Life Jackets are designed to keep the wearer between 33 and 55 lbs. (15 – 25kg) afloat.
Infant Life Jacket
These life jackets are Child Life and are designed to keep the wearer who weighs less than 33 lbs. (15 kg) afloat.
The required performance of the lifejacket will also be determined by analyzing all potential risk factors, including the following:
- The potential wearer’s stamina.
- The time the life jacket needs to work (how close are the potential rescue services.)
- The activities the vessel undertakes (deep sea or inland waters)
✅ Properly Fitting/Donning A Life Jacket
This section will teach you how to choose a life jacket correctly to ensure it works effectively in an emergency.
A life jacket that does not fit perfectly is better than nothing. But, the optimum solution is to have a life jacket that fits well and the user is happy to wear.
Anyone who regularly travels on the boat should have a well-fitting unique life jacket that is theirs.
It is also worthwhile keeping several general-use life jackets of different sizes for visitors.
A life jacket should be comfortable and worn as a choice rather than by instruction.
Always let the regular user choose a color and style of lifejacket that suits them. If they are happy with it, they will be more willing to wear it constantly.
The following is the list of factors to consider when fitting a life jacket:
✔️ Only select life jackets warranted by the United States Coast Guard (USCG) or SOLAS.
✔️ Select the most appropriately designated life jacket (adult, Teenager, Young Person, or infant).
✔️ Choose the most appropriately rated life jacket according to its Performance LEVEL and TYPE.
✔️ Select the size life jacket that matches the measurement of the wearer’s torso (circumference).
✔️ Test the life jacket by putting it on, zipping, or buckling it up and have someone check it for fit.
✔️ Hold the handle at the back and see if you can pick it up without slipping it off over the wearer’s head to check that it fits.
🦺 Additional Safety Features:
Some life jackets have additional safety features incorporated that may include the following:
- Lights
- Whistle
- Neck pillows
- Pouches or pockets.
- Rings to thread a rope through and keep all of the survivors together.
🔑 Key takeaways
Carrying and storing store life jackets on inland and offshore waters is required by law.
There are four categories of flotation provided by life jackets (Inherent, inflatable, hybrid, and special purpose).
Two types of rating are used to score life jackets Performance TYPE and Performance LEVEL life jackets.
There are four sizes of life jackets (adult, teenager, young person, and infant).
❓ FAQs
Do Life Jackets Work If You Can’t Swim?
Performance TYPE I Life jackets will rotate a person to ensure the wearer faces up in the water.
Once rotated, the life jacket will keep a non-swimmers head and nose above the water. This system works even if the wearer is unconscious.
How Do Life Jackets Inflate Underwater?
Life jackets that can inflate under water are called inflatable life jackets.
These devices have a small tablet that dissolves in water that works with a gas cartridge.
As the unit comes into contact with the water, the tablet activates the gas canister causing gas to be released and the life jacket to inflate.
