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Inflatable boats: basic criteria of choice

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There is a vast variety of inflatable boats of different design and purpose. While choosing an inflatable boat, take into consideration the following basic characteristics:

Driving force

There are inflatable rowing boats, powerboats and sailboats on the market. The latter is attributed to exotic vessels. The majority of inflatable boats can be adapted for sails. BARK boats are adaptable for sails in particular.

While estimating an inflatable rowing boat, pay attention to type and quality of oars and rowlocks. Traditional oars are not suitable for a small and compact one-man boat. BARK B-190 inflatable boat goes with paddles. You can read more about quality of oars and rowlocks here.

Motor inflatable boats always go with portable or stationary transom. Inflatable boats with portable transom suitable for low power motors are classified as rowing boats because a portable transom is an additional option of inflatable boat. If you prefer powerful motors, choose an inflatable boat with a stationary transom (to read more about it please refer to choosing a motor).

Important: a stationary transom must be an integral part of a boat. There are inflatable boats with portable transom which are designed in the form of stationary ones. Normally they are inserted into transom-holders and designed only for low power engines.

Transom are made of plywood, plastic or duralumin. Practice shows that plastic transoms are fragile. Duralumin transom can be bended. Therefore transoms made of water resistant plywood are the best. Water resistant plywood sheets are glued to each other by insoluble Bakelite resin. Moisture resistant plywood is not qualified for this use because it contains water soluble glues. While choosing a boat, always ask for composition of plywood.

Type of bottom

“Classical” inflatable boats have either flat or keeled (V-shaped) bottom. Motor boats normally have keeled bottom. It is assumed that inflatable boats with flat bottom are suitable for shallow waters because they have shallow draft. It is true only for hard body boats. Inflatable boats with flat or keeled bottoms have nearly the same displacement. Generally, inflatable boats have shallower draft than hard body ones.

Flat and keeled bottoms can be made of one-layer fabric. In this case the keel is attached to the bottom in the lengthwise direction and is inflatable. Fabric density starts from 1000 gr/m2 to 1100 gr/m2. Keeled bottoms must have a protection molding along the keel. Additional protection moldings along the seams at the sidewalls are also important because they protect a boat from friction during transportation. Even though additional moldings are quite rare, BARK inflatable motor boats have them.

Inflatable bottom is another option. Since 1920-s low pressure inflatable bottoms have become available on the market. High pressure inflatable bottoms became a reality back in 1980 thanks to invention of the material called airdeck. Two layers of fabric put together with the help of threads. The sandwich-like structure is sealed along the perimeter. The length of threads determines the thickness of the inflated bottom. The floorboard is not required because such bottom is hard. It has a heat keeping properties; your feet would feel warm onboard in the cold weather. These are advantages.

There are a number of disadvantages. In the course of time the threads tend to tear. The material being under high pressure becomes less friction and puncture resistant. If used frequently this kind of inflatable bottom would serve you only for a few seasons. It cannot be repaired. Inflatable boats with airdeck bottom are more expensive than “traditional” ones because the special material is dear.

Please note there are boats with inflatable bottoms made of normal low pressure fabric. Though their bottom is not as hard as airdeck they are reliable and comfortable. In fact some customers say that the airdeck’s hardness is questionable.

Another disadvantage is a keeled inflatable bottom. Such a boat has a V-shaped design of a bottom. It is not easy (and impossible in case of low pressure bottom) to stand on it. Therefore the floorboard is required. According to the customers, an appropriate floorboard can hardly be found on the market.

Finally, we would like to get down to the boats with hard bottom and hard body. Their body is made of fiber-plastic or of metal. According to Ukrainian standards such boats are classified as hard body inflatable power boats. According to International classification they are called hard body unsinkable powerboats with inflatable sidewalls or RIB (RIB stands for – rigid-hulled inflatable boat). The main advantages of RIB are their seaworthiness and speed performance. Officially they are branded race boats by Union Internationale Motonautique. Also they are suitable for fishing, preferably at sea. The main disadvantages of RIBs are as follows: 1) they require a large space for storage and 2) you will need a trailer for their transportation. Please note there are foldable RIBs (they can be folded through the length and breadth) and collapsible RIBs with modular body. Unlike traditional RIBs, such foldable vessels do not have deck. Their keeled bottoms have a V-shaped design, not comfortable without a floorboard. Not every car can carry a foldable RIB. RIBs are much more expensive than “classical” inflatable powerboat of the same size and passenger carrying capacity.

Type of a floorboard

There are solid and strip floorboards available on the market. Inflatable rowing boats can go without floorboard. Powerboats require floorboard in order to make a bottom hard enough for an efficient work of motor. The only exception is boats with airdeck. Strip floorboard is suitable for flat bottom inflatable powerboats. Inflatable motorboats with inflatable keels require solid floorboard.

Floorboards can be made of different materials. Laminated water resistant plywood is the best. The upper side of it should be laminated with a corrugated anti-slip film. The underside should be smooth to minimize friction between the floorboard and the bottom. A plastic floorboard is not durable enough to withstand loads. Therefore some customers can use a heavy-duty thick plastic which is heavier and more expensive than plywood one. However, a limited number of manufacturers offer it.

Floorboard is to be installed individually, piece by piece. You should fix it to the special clips in the bottom. Some floorboards are assembled in one solid loose laid carpet. Different methods of floorboard installation have been developed since 1930. Some of them are effective, some are not. Practice shows that loose laid carpets are not good enough because they move from side to side distorting the geometry of a boat. Therefore we recommend a traditional floorboard which can be fixed to the bottom.

Some floorboards are to be inserted in special grooves located at the bottom along the sidewalls. You can adjust the position of a floorboard by moving it to and fro. Remember about one disadvantage: such a sliding floorboard can slip away under your feet at the wrong time.

Some floorboards can be glued to the two-layered bottom. You can roll such an inflatable boat up with the floorboard inside quite quickly. Boats of this design belong to a special category called roll-up, i.e. boats with floorboard and stationary transom. Interestingly, any inflatable boat with the strip floorboard can be attributed to this category too. Only inflatable boats with a sliding floorboard cannot be rolled up because of grooves.

Solid floorboard is assumed to be hard - it is often referred to as hard floor. It can be made of different materials: a duralumin and inflatable fabric for solid and plastic or plywood for modular ones. Plywood is the best material for it in terms of reliability, comfort and price.

We described deficiencies of plastic and duralumin floorboards before. The latter is expensive, fragile and irreparable. Until now no manufacturer offers a reliable and quality plastic flooring. Thick duralumin sheets are durable but quite heavy and expensive. They heat up quickly when exposed to sunlight in summer.

Inflatable floorboards are assumed to be light-weight, durable and hard thanks to high pressure. In fact their hardness is questionable. The best inflatable floors are made of special material called airdeck. Therefore an appropriate inflatable floorboard is quite expensive. You can find a vast number of cheap inflatable floors made of traditional boat fabric on the market. In fact, they are not durable or hard. Quite often all kinds of inflatable floorboards are mistakenly called airdeck. Remember about it while choosing an appropriate one. Beware of fake.

There is a bilge flooring in the form of sole-book. It looks like a solid modular carpet. The carpet’s parts have a flexible connection allowing you to fold it like a book. This carpet is neither hard nor reliable. It has the same technical properties as bilge carpets. Inflatable boats with sole-book floorcovering are attributed to roll-up category.

The type of floorboard has a direct impact on usability of boat. If you prefer fishing in standing position, choose a solid carpet. If quantity and layout of bilge flooring are correct, you will be able to stand firm on it. And you can hardly stand on the floor of a boat without a floorboard, be it a flat bottom or V-shape inflatable boat.

Material of tubes

Since 1980s the multilayered structure of the tube’s material as a quality character has become an advertizing trick. Today many customers think that the quality inflatable boat should be made of five-layered material. You are strongly advised to remember about the fact that according to the International standard the inflatable boats must be made of multilayered boat fabric. Always remember that multilayered tent cloth or film material do not fit for boats. Multilayered boat cloth consists of a dense core material (cord) covered by polymers on both sides. Compatibility of a core material and polymers is paramount because it has to do with adhesion and durability. The density of boat cloth is also important. In fact the quantity of layers does not matter much.

There are two production methods of multilayered boat cloth. The core material is covered by polymers in the form of a glue-like substance or in the form of adhesive layers (adhesive or solvents). The most popular five-layered boat cloth consists of a core material covered by 2 layers of neoprene on the underside and by neoprene and hypalon on the upper side (you can find more about it below). Taking into account layers of primer and adhesive, some advertizing experts say about seven layers.

At any rate all layers must be bonded en bloc. Cross section of a boat cloth reveals at least three layers consisting of the core material and polymers on both sides.

Core material consists of synthetic polymers. Interestingly, some manufacturers produce outdated rubber inflatable boats made of natural cloth (cotton). Polymeric core material consists of polyester or polyamide fibers (it can be nylon-6,6 or nylon-6, i.e. capron). Polyester is inferior to nylon in terms of bend strength though this physical property is negligible when you compare different inflatable boats (you can learn more about it herebelow). In the majority of cases the polyester is the most suitable material for boat cloth because it has high tensile strength and impact resistance. This is the reason why BARK boats are made of fabric containing polyester.

The coating consists of plastomer (plastic) or elastomer (rubber). PVC is the most popular plastomer while polyurethane and chlorsulfonated polyethylenes (hypalon) are the best elastomers in terms of physical properties. Hypalon is inferior to polyurethane but is cheaper. Only special purpose boats have a polyurethane coating. Hypalon is often combined with neoprene. Originally neoprene and hypalon were trademark of DuPont Corporation. In 2010 the production of hypalon was discontinued. Since then thousands of manufacturers have been producing their own “hypalon” of different qualities. At the same time there are inflatable boats made of outdated low quality rubber of the first half of XX century. For instance, it is butyl rubber.

There are thermoplastic elastomers which become resilient as rubber when heated and turn hard as plastic when cooled. Some contemporary modifications of PVC applicable in boat fabric have similar characteristics as thermoplastic elastomers. PVC is in the lead in terms tailor-made modifications. Inflatable boat’s tube consists of PVC modified by polyurethane, hypalon and elvaloy. The latter improves durability and resilience. BARK inflatable boats are made of this kind of boat fabric.

Today PVC is the most suitable material for inflatable boats. In fact it did not measure up to hypalon in 1990-s. Thanks to the modifications of PVC-based boat fabric it has become as efficient as hypalon recently. In terms of airtightness, abrasive hardness, resistance to corrosive environment and operating temperature up-to-date PVC is equal to hypalon.

PVC has a slightly lower UV resistance, lightfastness, tear and bending strength performance than hypalon though. Does it really matter?

If exposed to sunlight for 24 hours a day near the Equator, PVC would become ineffective at the beginning and hypalon would fail at the end of the fourth year in use.

Hypalon and PVC have a very strong tear and puncture resistance performance.

Bending resistance determines the number of times an inflatable boat can be effectively folded and unfolded. If unfolded daily, hypalon-based boat would serve you for 600 year, PVC-based boat would last for 410 year without any crack along the break line.

Please note that the most expensive PVC boat material is cheaper that quality hypalon.

Important: a quality inflatable boat must be made of boat fabric. Tent cloth or film materials are unacceptable. Multilayered tent cloth is not suitable because it is neither durable nor resistant to corrosive environment and UV. Film materials consist of polymer with no core material inside. Inflatable boats made of film material are branded inflatable playthings while inflatable boats of tent cloth should be disqualified. However inflatable boats of film and tent materials are wrongly advertized as vessels for fishing! Beware of it!

Rubber vs PVC inflatable boat. Obviously you would agree that PVC inflatable boats have an advantage. Technical properties of contemporary PVC and rubber are the same while PVC boats are considerably cheaper. You can still see some outdated rubber boats at low price. Remember their technical properties do not measure up to PVC boats. At some point excessive resilience of rubber boat turns to the disadvantage. Daily temperature difference and air pressure fluctuation inside of the tubes and small water waves alter the shape of a rubber boat making it less maneuverable.

Accessories

Along with the quality of material and of mounting accessories, efficiency and ergonomics are paramount. Quality wood belting attached to outer sidewalls should have a splash board. This accessory protects sidewalls from shocks and friction against mooring berth or reed and keeps cockpit away from sprinkling. Wood belting is very useful accessory particularly for inflatable motor boat. Handles are important too. It is advisable to have a fair number of multifunctional handles. BARK inflatable boats have enough knecht-handles that allow you to wind the rope around it. Generally, BARK inflatable boats are a good example of a good product with useful accessories.

Inspect the boat carefully before buying it.

Passenger and load carrying capacity

Passenger carrying capacity of inflatable boat is estimated as 1 man with the weight of 75 kg. One seat for an adult is considered two seats for kids under 7. Load carrying capacity of quality inflatable boats is higher than the estimated weight of passengers in order to leave some place for outfit and luggage. While choosing an inflatable boat, take into consideration the following aspects:

  • Part of load carrying capacity goes to motor, fuel and battery.
  • Boat should be loaded up to 70% of it maximum.
  • Passenger carrying capacity is dependable upon volume and weight of luggage. For example, one duffel bag may occupy one passenger seat.

Important!

State registration is mandatory. Every country has its own rules and regulations as to registration of inflatable boats. An inflatable rowing boat not exceeding 2,5 m in length is subject to State registration. If such a boat has a portable transom, it should be registered. Please note that any inflatable motor boat is subject to State registration (to learn more about it refer to State registration).

Additional options. Manufacturers usually offer the same basic warranty conditions and different additional options. Styling package and additional accessories for inflatable boats are really valuable.

Certification. While choosing an inflatable boat, always make sure it has a certificate. The latter is mandatory in many countries. It contains the name of model and the series number. The certificate is issued by the authorized agency of country of origin. BARK inflatable boats have Certificates of small craft issued by Shipping Register of Ukraine valid in Russia, Belarus and Kazakhstan. Learn about regulations as to certification in your home country before buying an inflatable boat from your local dealer. BARK inflatable boats are certified in full conformity with the local regulations in all the countries in which they are available.

Whichever inflatable boat you want to buy always make sure it has a Certificate with rubber stamp on it. In default of both never get it. Choose another certified inflatable boat.

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