Life Jackets, Safety Equipment, Seago, Spinlock -


Life jackets can be the difference between life and death, so there shouldn’t be any compromise when it comes to picking out which one best suits you and your needs. 

As sailors ourselves, we at Plain Sailing Chandlery know how important this decision is. But, with so much choice, we understand how difficult it can be to get your head around the different varieties and details. 

To help you with your choice, we’ve compiled a guide for you, including the different types of life jacket, their features, and how each might be the one for you.

The principal feature of a life jacket is its firing mechanism, meaning what triggers it to  inflate. This is a vital aspect to consider when choosing your life jacket and depends mainly on what kind of activities you participate in, but also on what makes you feel comfortable and safe when on the water.

There are three main inflation methods for gas life jackets: Automatic inflation, manual inflation, and hydrostatic (hammar) inflation, with these being either automatic or manual. 

For most water sports, we suggest Co2 inflated life jackets, simply because of their suitability and dependability in most situations.

Manual Inflation Life Jackets 

Manually inflated life jackets are simple to understand, with their primary feature being a pull chord. When pulled, the chord releases a pin that fires into a Co2 canister, releasing air into the life jacket and inflating it.

The main positive of a manually inflating life jacket is that there is no risk of false activation, which can be the case for automatic life jackets. This means that the life jacket will only inflate once the user has activated it themselves.  This system can be more suitable for low-risk situations.

However, if the wearer is unconscious, suffering from cold water shock, is experiencing high levels of panic, or has limited mobility, they may not be able to pull the chord and won't be able to inflate the life jacket.

For high-risk water sports such as yacht racing we suggest going for another type of life jacket, but for low-risk water activities, these life jackets are perfect! 

We offer a wide variety of manually inflated life jackets at great prices, such as the Seago Classic 190N and the Seago Seaguard Life Jacket. Visit our website to get yours today!

Automatic Inflation Life Jackets

For higher-risk activities, automatic life jackets are probably the choice for you, and are widely used for yacht sailing.

They inflate when an automatic firing head with a small pellet or bobbin, which holds back a strong spring comes into contact with water. When contact is made, the firing head quickly dissolves, releasing the spring which then pushes a pin into a gas bottle, inflating the life jacket. 

A positive aspect of an automatically inflating life jacket is that, unlike with a manual life jacket, if the wearer is unconscious or is in a situation where activating the inflation themselves is difficult, the jacket will do the work for them. 

However, for activities where being soaked by big waves or being out in driving rain are common, there can be instances of false activation due to the low level of water contact needed to inflate the life jacket. This can cause issues for sailing, as weather conditions and splashing from water can accidentally inflate the life jacket. 

Despite this, these life jackets are on the whole highly dependable for most water sports where you are not expecting to get too wet. We offer a wide variety of automatic life jackets, including the Spinlock Deckvest LITE Life Jacket 170N and the Spinlock Deckvest LITE + (with harness) 170N, both of which are also available on our website.

Hammar (Hydrostatic) Life Jackets

A third option is a hydrostatic firing system, more commonly known as a hammar, life jacket. These are very similar to automatically inflating life jackets but have minor varying details to keep in mind.

Like automatically inflating jackets, these also inflate when they come into contact with water. However, their firing mechanism won’t activate unless the wearer is fully submerged in water, meaning they are more suitable for activities in the driving rain or when being soaked by water without falling in.

The pellet that activates inflation, unlike an ordinary automatic life jacket, is protected by a case, meaning that water will only get to it when fully submerged. 

These life jackets are excellent for those taking part in activities in rough waters, such as off-shore yacht racing, and give you the peace of mind that your life jacket is ready for any scenario you might come across. For any yacht sailing, we highly recommend them!

We also offer a wide variety of hammar life jackets, including the Seago Active Pro 190N Harness Life Jacket,  Seago 3Dynamic Life Jacket, and Spinlock Deckvest VITO, all of which are available to buy on our website

What Else To Keep In Mind?

Together with its firing mechanism, a life jacket also has several other features and specifications to keep in mind when choosing one. These are also incredibly important and could massively weigh into your decision, again being based on what sport you’re taking part in, and how comfortable you feel around water.


A major thing to look out for is how much buoyancy a life jacket has. Buoyancy is measured in Newtons (N), with 10 Newtons equaling 1kg of buoyancy.  

The amount of buoyancy you’ll need is based on two factors: where you are (sea, lake, etc?) and what you’re wearing (how many layers are you wearing? How heavy are your clothes?)

To help you, we’ve made a simple guide to the different buoyancy standards and what specific activities usually require: 

  • 50N - Should be used in calm, sheltered waters where help is nearby.
  • 100N - ample buoyancy for children’s life jackets and adults in calm waters
  • 150N - Often used in coastal and inshore waters when sailing, but can be used for less clam weather.  If the sailor isn’t wearing heavy clothing, there is usually enough buoyancy to keep someone’s head above water.
  • 275N - Usually used for offshore or commercial use when heavy clothing is worn. This level of buoyancy will be adequate to keep a person who has gone overboard as safe as they can be in the water. 

All of our life jackets are CE or ISO certified, and their buoyancy is listed in their descriptions on our website


A question that is often asked is if size makes a difference when choosing a life jacket. 

When it comes to height, most life jackets are adjustable, which is why there aren’t any size options. However, with some life jackets, there are size options in order to ensure an exact fit girth-wise. So, it depends on what you’re looking for and which brand you want to go with. 

Weight is also an important factor to consider. If you weigh more or are wearing heavier clothing, we suggest you opt for a life jacket with a higher level of buoyancy, which will ensure that, if you do fall overboard, you will be kept above water. 

We’re here to help!

At Plain Sailing Chandlery, we offer a wide variety of manual, automatic, and hammar life jackets, all of which are at the highest industry standard.  We strongly recommend you wear a life jacket, even in fair weather.  It is always better to be safe than sorry.

If you have any questions, or want to browse our wide variety of rope, buoys, clothing, and much more, please visit our website at

We’re always here to support your sailing adventures!