Sib is an abbreviation of Soft Inflatable Boat. I have put together this guide so you can see the merits this type of boat has to offer. Hopefully the information on inflatable boats (sibs) below will help when you make you first purchase.

No boat type is perfect for everyone, all have there particular advantages and disadvantages. Some do come pretty close though. Here we will be looking at Sibs. This type of boat has many uses and advantages over traditional hard bottomed boats. Its also has disadvantages too, which we will go through in further detail below.

When people think of soft inflatable boats, often their first thought is of cheap tourist type boats. This style are often sold at sea side resorts for around £50 depending on size. These are toys and are designed for swimming pools or to be used in water no deeper than a foot or so. The material is flimsy at best and they are potential death traps. If you try going out further into the sea or god forbid fishing, you will most likely get wet or worse. Like the toy in the picture below they are neither safe or stable.

Sibs are a different kettle of fish all together, these are designed for the particular task at hand. They come in category D and C guises. This means they are capable of handling inshore seas with ease in the right weather conditions. Moreover they are able to take outboard engines, the HP differs depending on size and style. I would always choose a Cat C for safety reasons unless I was sat less than a few hundred yards from shore. The category is shown on the manufacturing plate as is the capacity and maximum outboard size.

The main 2 advantages of Sibs over traditional hard bottomed boats in my opinion are portability and storage. Checking pack size before purchasing you can easily see if it will fit in your car. Secondly it can be kept in a much smaller area than a hard bottomed boat (ie the house). Hard bottomed boats usually require payed storage, a big driveway or garage. That said
Sibs are available in various sizes and generally range from 2.3 metres to 4.2 metres for personal use. Above this size, setup with attached outboard engine weight becomes an issue for the casual user. They are available in sizes up to around 7 metres, these are usually used by diving clubs, search and rescue or for commercial uses.

Sib manufacturing materials

  • Hypalon
  • Polyvinyl Chloride (PVC)
  • Polyurethane (PU):
Hypalon fabric

Hypalon: This is a synthetic rubber coating onto polyester or nylon fabric and can have a neoprene coating on the rear of the fabric. The rubber coating is hard wearing and lasts for over 20 years or more, if you look after it properly.

The joints are glued by butting the fabric together and applying glued cover strips or tapes over the seams, or the sections can be overlapped and glued. Hypalon fabric is considerably more expensive than PVC, it has a similar cost to decent PU fabric.

PVC fabric

PVC: A plastic coating that known chemically as polyvinyl chloride, it is applied as a sandwich coating to polyester or nylon fabric. PVC is not usually very flexible as standard and requires a plasticizer to shape better.

Older PVC has a bit of a negative reputation among Sib owners as the additive can degrade with exposure to UV light. This makes the material brittle leading to cracking. Modern advances have addressed this issue and good PVC fabric manufacturers provide 10 year guarantees on marine grade fabrics.

A PVC tube is the cheapest material option bit it can last for up to 15 years and is used in most mass-production boats. The joints can be rapidly welded using thermal or high-frequency welding or they can also be glued, making repairs quick and easier.

PU (Polyurethane): PU is the newer (ish) fabric . Tests support manufacturers claims that PU holds air better than Hypalon, it has high levels of abrasion resistance combined with tensile strength. The price is similar to decent Hypalon but its still far more expensive than PVC. Quality PU has a life span to 15 years, but there are some that are still going strong after 20 years.


Sibs have 3 flooring options which give them slightly different characteristics and give subtle change there attributes . The perfect solution is different for everyone and is usually dependent on 2 things. Requirements of the boat and budget.

Slatted floors

Usually reserved for tenders to much larger boats. Slatted floor Sibs are generally lighter and more easily stored if needed, moreover they are the cheapest option. Slatted floor are usually available in Sib sizes 2.3m – 3.3 metres. Quick to setup on the go.

In terms of performance, in my opinion they are the worst performers. Slatted floors are less stable to stand in/on and give a flat bottom, which gives poorer ride handling. Slatted floor Sibs also tend to have a reduced capacity in terms of the HP outboard engine they are able to handle. Inflatable keels are not Struggling to make use of the available power as efficiently.

That said they are more cost effective and just as safe as their alternatively floored sibling. Perfect if you are on a budget, don’t mind reduced speed and planing abilities. This makes them perfect tender craft platform or as cheaper fishing boat.

Air Deck

Airdeck Sibs are in my opinion the great all rounder, practical, as like slatted floors they can be used as tender too. The boat in its entirety can be deflated for storage, unlike solid floors which can be heavier and bulky. Air Deck Sibs are generally available up to around 4 metres in length. They are similarly priced to their hard deck siblings.

Mordern airdeck sibs produce a pretty solid high pressure flooring solution, this is far more stable to stand on than a slatted floor. This in turn gives you a more solid fishing platform if that was you are after. Some worry about damaging the airdeck with hooks or knives but simply covering with a yoga mat or similar material will offer protection for piece of mind. A high pressure inflatable keel under the airdeck also has a few advantages. It provides you with a little extra buoyancy but its main purpose is stability when turning. An inflatable keel helps with directional control moreover makes it easier for the boat to get on the plane. The V shape helps the boat grip for want of a better word by cutting into the water like a traditional hull. Slightly heavier than slatted decks but more practical if weight is of less concern. Slightly easier on the backside when on choppy water too.

Airdecks are able to take comparative engines equivalent the solid deck sibs allowing for more performance. If you are into fishing this will allow quicker access to fishing grounds, or reaching those secluded beaches.

Solid Deck

As it says on the tin…a solid deck. These come in two guises, marine ply-board or aluminium. These give the most solid floor feel like and actual boat would. Solid decks tend to be favored by some anglers as it avoids accidental punctures to the deck.

The aluminium floors tend to be lighter than the plywood decks and should last the lifetime of the boat. Plywood will too providing its looked after. Some but not all solid deck sibs are able to take slightly higher HP outboards too.

The advantages of the solid deck is a more rigid, this creates a more stable platform. Increases power possibilities, it is also able to use the given power slightly better than an air deck floor. Most modern solid deck sibs have inflatable keels which aid in directional stability control and help them get on the plane quicker. The solid floor keeps the inflatable keels in a more solid central position, some air deck allow a bit of keel movement.

So solid floor sibs give more of a true boat feel with the advantages we have talked about but still do not suit everyone. Price wise they are comparative to air deck boats so are direct competition.

Solid deck sibs have several disadvantage to the other sib flooring types, the main (in my opinion) is weight. Solid decks can add up to 40% more than their air deck siblings, when launching solo it is something to be considered. The pack down size is also increased due to the flooring, this increases the storage space needed at home as well as in the car when transporting. There is also a small learning curve when setting them up for the first few times. To negate weight and setup time, some keep there solid decks inflated on trailers, again if you have space this is ideal. (could replace with a rib for increased performance.)

There is no perfect sib for everyone or maybe there is, it all depends on your personal circumstances. Hopefully the above has been informative and will help you make a decision on purchasing your first sib.

Please leave comments below if you feel I have missed anything, lets make it easier for people to make informed decisions, when buying their new sib.

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