A rigid-inflatable boat (RIB) or rigid-hulled inflatable boat, (RHIB) is a light-weight but high performance and high capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwhale. The design is stable and seaworthy. The inflatable collar allows the vessel to maintain buoyancy even if a large quantity of water is shipped aboard due to bad sea conditions. The RIB Boat is a development of the inflatable boat / boat’s.
ASIS Rigid inflatable boats are used as work boats in trades that operate on the water, including use as lifeboats and military craft, where they are used in patrol roles and to transport troops between vessels or ashore. Rigid Inflatable Boats ( RIB’s) are now getting increasingly popular in the leisure Market in USA, UK, Ireland Scandinavia, Mediterranean, Russia and throughout Europe and the Middle East taking over from the traditional speed boat.
The first commercial RIB is believed to be launched at the January 1969 London Boat Show.
The combination of rigid hull and large inflatable buoyancy tubes seems to have been first introduced in 1967. RIB’s were then introduced for the first time as lifeboats on the Solent, England in 1970.
ASIS RIB’s are commonly 4.1 to 9.8 metres long. A Rigid Inflatable Boat is often propelled by one or more outboard motors or an inboard motor turning a water jet or stern drive. Generally the power of the motors is in the range of 5 to 350 horse power.
RIB’s are used as rescue craft, safety boats for sailing, dive boats or tenders for larger boats and ships. Their shallow draught, high manoeuverability, speed and relative immunity to damage in low speed collisions are advantages in these applications.
RIB’s Boats up to about 8 metres in length can be towed on trailers on the road, this coupled with their other properties is making them increasingly attractive as leisure boats.
Rigid Inflatable boats are designed with hydroplaning hulls. Due to their low weight Rigid Hull Inflatable Boats often out-perform some types of similarly sized powered boats, although a pure fiberglass speedboat with similar dimensions is typically faster, due to its lighter weight and more arrow like-shape.
RIBs can also generally cope better with rougher seas, although this may be partially due to an increased level of confidence, in knowing that a Rigid Inflatable Boat is hard to sink, and better absorption of heavy loads by the flexible tubes, which therefore make heavy seas less unpleasant. Rigid Hull Inflatable boats are used as Rescue boats as they can be used in most sea states.
The maximum speed of the RIB depends on its weight, power, load, and sea conditions. A typical 6 metre RIB, with six passengers, 115 horsepower engines, in the sea in force 2 is likely to have a top speed of around 30 knots . High performance RIBs may operate with a speed between 40 and 70 knots, depending on the size and weight.
The hull is made of steel, wood, aluminum, or more commonly, a combination of wood for the structure and glass-reinforced plastic (GRP) composite for the shaped and smooth surface. Some manufacturers also weave Kevlar into the GRP sheets for extra strength. The hull of a RIB is shaped to increase the performance of the boat in the water. "Deep-V" hulls cut through waves easily but require greater engine power to start planning than "shallow-V" hulls, which plane at lower speed but with a more uncomfortable ride. As with the design of most boat hulls they represent a compromise of different design characteristics.
The tubes are usually constructed in separate sections to reduce the effect of a puncture, each with a valve to add or remove air. Larger boats (9m+) have 6 or more chambers with a valve for each chamber. The more chambers a boat has the more redundancy the boat is considered to have. This is because if only one chamber is damaged then the impact the damage has on the boat is much less. Dark tubes often have pressure relief valves as the air inside them expands when exposed to sunlight. This prevents the tubes bursting from over pressure. Common materials for the tubes are Polyvinyl chloride, Polyurethane and Hypalon.
As a material for building tubes, polyvinylchloride (PVC) has the disadvantage of lacking flexibility. To make it supple, an additive is used with the polymer. This additive vaporizes as the material ages, making the PVC brittle and allowing it to crack easily. A PVC tube is the cheapest option and lasts approximately five years.
Tubes made of polyurethane (PU) are difficult to manufacture and hard to repair. PU has the great advantage of being very tough, it can be made knife-proof or bulletproof. Unfortunately to make PU airtight, it has to be used in layers, combined with neoprene. The biggest disadvantage with PU is that it ages quickly: thermal and mechanical wear-and-tear and exposure to ultraviolet-light are problems. A high quality PU-made tube lasts 10 to 15 years.
PU tubes are often to be found on commercial RIBs, in applications where strength and durability are needed. Replacing the tubes when they wear out, usually costs one third of the complete RIB.
Tubes made of Hypalon are easy to manufacture and can be repaired with simple puncture repair kits. Hypalon is not airtight and so must be combined with Neoprene when used to build tubes. Tubes made with Hypalon and Neoprene layers can last 30 years or more.
Although early in its life a PU tube will be stronger than a Hypalon/Neoprene tube, by the age of five years they have similar levels of durability, which is why Hypalon/Neoprene tubes are often to be found on RIBs that are owned by commercial and high value leisure users. Hypalon is probably the most popular material used for the construction of RIBs manufactured in the UK.
Larger RIBs can have hard-tops or wheelhouses made of GRP or aluminum. Wheelhouses offer protection from the elements to both the crew and passengers - and can also protect equipment such as suspension seats and navigation equipment. Some RIB manufacturers, particularly those popular in Ireland and the West Coast of Scotland provide optional canopies which form fabric and Perspex wheelhouses but can be easily removed in good weather. Increasingly, RIBs are becoming available with small cabins (usually with accommodation for 2 people and in some cases sea toilets or chemical toilets, widening the application of RIBs as cruising craft.
Rigid Buoyant Boats are based on the concept of a RIB but with a tube/sponson manufactured from a solid material such as moulded polyethylene or aluminum and therefore being much more robust than the fabrics commonly used. Boats with foam filled collars such as the (SAFE) boats employed by the US Coast Guard can also be classified as Rigid Buoyant Boats rather than "true" Rigid inflatable boats as the collar is solid foam rather than inflated. The handling tends to be very similar to a RIB; likewise they will remain afloat (buoyant) even if completely flooded. Aluminum RBBs tend to be bespoke (custom-made to specification) or low-volume products whilst the tooling cost of rotomolded polyethylene boats tends to require these to be higher volume products. At least three manufacturers are producing rotomolded boats of this type.