BACK IN THE 1980S, it was largely the diving community that pioneered the use of RIBs as leisure boats. Before that, rigid inflatables were pretty much the preserve of rescue organisations and the commercial operators, which, from the early '70s, had understood the RIB's rugged sea-keeping virtues, the stable platform it provided and its natural load-carrying ability.
So perhaps it wasn't surprising that divers quickly realised that this new breed of vessel had all the attributes needed to make a very useful dive boat.
The fact that this inflatable hybrid could travel by trailer, and was relatively inexpensive compared to running a traditional 'hard boat', also proved key. It was in fact diving enthusiasts who started up RIB manufacturers such as Humber and Delta.
Frank Roffee of Humber Inflatables started his boat-building career while still making caravans. Deciding to make an inflatable for his local club, he used hospital-bed fabric held together with glue from Woolworths!
The design was refined, including the use of black neoprene as sponson material, and within a couple of years Roffee was exhibiting at events such as the BSAC Diving Officers' Conference, selling his 'new invention' for ?45!
Soon after, in collaboration with 'RIB supremo' Paul Lemmer, Roffee built his first rigid inflatable, the Humber Attaque. This successful hull design is arguably still one of the best of its type, and helped make Humber one of the most prolific RIB-builders in the UK by the mid-'90s. It still builds RIBs of all sizes and types.
Charles Dyas, now managing director of one of the world's most successful commercial RIB brands, started his professional career in the boating industry by selling Humber RIBs, largely to fellow-divers. When striking out with his own design, it is alleged that he had great difficulty preventing the boat from stuffing its bow in adverse seas.
Legend has it that he made the decision to keep increasing the height of the bow until it no longer buried itself into the foot of a following sea - and so the distinctive 'Delta bow' was born!
Thanks to this bow design, which provided equally capable sea-keeping at both displacement and planing speeds, and the attributes of a wide beam and strong construction, the Delta remains one of the finest load-carrying and most seaworthy RIBs on the market.
The Delta's successful high-sheer profile has since been adopted by other builders such as Ribcraft and Tornado in the UK, as well as overseas builders Lencraft and Duarry. Though no part of the Delta product range, the original 'Delta Dash', popular with so many divers over the years, is still seen around the UK in 5.5m and 6.5m format, faithfully carrying its cargo of divers and their kit.
Another brand popular for many years with divers is the Tornado.
Like Roffee and Dyas, Tornado's founder David Haygreen came into RIB-building mainly because of his professional involvement in commercial diving.
Despite the many variations of engine installations, console and seating in the current model range, the Tornado RIB and, more recently, its Viking stable-mate, continue to acknowledge divers' needs, especially in terms of their fit-outs.
Although the RIB market has progressed and evolved beyond all expectations, divers' requirements have changed little over the years. So what makes a good dive RIB?
Let's start from the bottom up, with the RIB's most critical component.
The inflatable boat was the popular forerunner to the RIB and still fulfils a number of dive applications, even today.
The pure inflatable, being essentially flat-bottomed, is best suited to short journeys, so is commonly to found on survey vessels and the like. With its flat bottom profile and low weight, it is also useful for beach-launching, as it can be carried or 'trollied' into the shallows before loading with kit and divers.
As for rigid inflatables, many hull designs are available - medium-vee, stepped, deep-vee and even catamaran.
Stepped hulls, though deep-vee in design, are built with high performance in view, so are unlikely to be suitable for dive-boat application.
'Bluewater RIBs', as they are generously known, are typically made on the Continent and tend to feature medium-vee hulls which, as on a pure inflatable, are stable at rest and good load-carriers.
However, they are rarely suited for use offshore or in the types of sea conditions found in UK coastal waters.
They are built mainly for the Mediterranean where, contrary to popular belief, the seas are short and can be very rough. So, paradoxically, the RIB market in these parts is flooded with boats that provide a hard and often uncomfortable ride!
A medium-vee hull needs less horsepower to get up on the plane, but the downside to a lot of bluewater RIBs is that their interiors are too cluttered with passenger seating and extravagant consoles to allow dive kit to be carried. Refined internal finishes such as grp deck-liners may look the part, but you need to check whether they are strong enough for diving purposes.
Gas cylinders can give any deck surface a hard time, so whichever RIB you buy, check the liner strength and construction quality. You might want to ask the builder to forget the liner and provide a basic flow-coat and Treadmaster finish instead.
This is generally a more suitable surface if you feel you might need to retro-fit further bottle racks and so on, needing to screw and Sikaflex directly into the fabric of the hull.
Catamarans are an interesting option, as they offer unique benefits to divers. Coupled to a hydrofoil, the catamaran hull configuration generates great lift and stability when underway.
As with the South African-made Hysucat RIB, the design also requires less horsepower, thanks to the hydrodynamic efficiency of its foil. It can also run in short, steep seas with a minimum of 'porpoising' or slamming - good for occupants and reducing the chances of dive gear being damaged.
The twin hulls of a cat increase deck space significantly compared with a typical monohull, so
a dive club or individual looking to buy a dive RIB might be able to reduce the required 'LOA' - length overall. This reduces initial financial outlay, berthing charges and fuel costs, with less horsepower needed, and eases storage.
Pure deep-vee hulls, with their varying spray-rail and chine combinations, are perhaps the most successful and best-loved form of sea-going RIBs, and pre-date the birth
of the RIB in the late 1960s. A genuine deep-vee hull, from the likes of Delta, Tornado and Humber, aims to combine the benefits of performance and sea-keeping in one neat package.
A deep-vee hull is well suited to divers seeking a stand-alone craft that can handle short-distance excursions along with longer, coastal or even offshore journeying. An inflatable tube, or sponson, positioned along the upper line of the hull so that it just touches the waterline at the boat's aft end, makes an outstanding combination.
The result should be a well-found RIB that can perform even when heavily laden. It will have huge lateral stability sufficient to withstand all that a team of divers might subject it to, outstanding rough-water get-you-home capability, and be a real multi-tasker.
But there has to be a compromise.
The downside is that the deep-vee requires a relatively high degree of horsepower to propel it, which means a higher purchase cost and greater fuel costs.
When choosing the powerpack, it's wise to err on the side of having more than enough power. Too little horsepower/too small an engine will render the boat vulnerable in heavy seas, and when carrying a full load it will labour.
You will have to push the engine to the max and burn big amounts of fuel.
It's your decision. If you're thinking of diving on wrecks that require travelling more than two to three miles, perhaps in a testing sea state, and if maintaining speed in rough seas is important to you, you should probably be considering a deep-vee-hulled RIB.
The criteria for the boat's interior normally revolve around the need for uncluttered or free deck space.
While many dive RIBs have all their bottle-racking in the stern directly behind the helm and crew seating, this can cause the boat to be bow light and unbalanced in its handling.
Consult the builder on ways of balancing the boat by careful positioning on deck of key items, including crew seating.
Dive boats generally need to carry high payloads, so on a 5-6m RIB consider positioning the console, fuel tanks, battery and so on well forward to achieve the deck space required in the stern. This will also help to balance the RIB when the bottle-rack in the aft area is full.
On a larger RIB, 7.5m and over, with the seating pods positioned on the aft deck you might even consider mounting your bottle-racks ahead of the console to help counter-balance the vessel when underway. Or, in the case of a cox'n wanting to maintain a watchful eye over his passengers, it may even be desirable to set the seating pods ahead of the helm console.
On the subject of seats, the traditional jockey console has proved the best suited to a diver's needs. It takes up little room, normally benefits from having storage within and can be straddled easily even when wearing a heavy drysuit. In a fast planing boat such as a RIB, the jockey seat also allows the user to stand, allowing the ride to be taken on the best shock absorbers yet invented - human legs!
In a dive RIB being used offshore, the transom must possess suitable scuppering to allow any shipped water to be drained quickly and efficiently. This is usually done via elephant's-trunk type scuppers, a simple, non-mechanical means of ejecting the water off deck with only moderate forward power needed.
Never rely on electric bilge pumps alone, because they will fail if the boat's electrics are compromised, as when a severe swamping penetrates the battery compartment. And with that in mind, ensure that your battery is positioned securely in a dry area of the boat - perhaps a waterproof section of the helm console, rather than in a wet back locker!
You can't have too many handholds on a RIB, so grab-points to the back of the jockey seats, handles to the helm console and lifelines to the tubes will all prove invaluable. The helmsman is usually the most secure person onboard, as he has the wheel to hang onto, so he may be less aware of how hard the going is for his passengers.
Footstraps are another very effective means of adding to onboard security. Usually made from a webbing fabric and screwed firmly to the deck, these can be provided for everyone.
On high-quality RIBs, the sponsons are generally made of polyurethane or hypalon and, as they provide seating for divers, their height above deck is important. The Avon Searider, and craft from Tornado, Osprey, Ribcraft, Delta, Humber, Coastline, Ocean Dynamics and Redbay, all feature deep decks and have tubes positioned to allow for such use, while not being set so high as to allow the boat to rock laterally at rest.
The likes of Revenger and Scorpion build high-performance hulls with higher-set tubes that are positioned to lessen drag when underway. This type of design will be relatively stable at rest when fitted with a diesel engine, but tends to rock if fitted with lighter outboards - and a key priority for any diver is a stable platform.
The other item of the boat's fit-out worth mentioning is the arch mast or A-frame, which carries essential navigation lights and 'flying gear' - aerials for the GPS/sounder and fixed 25W VHF. Depending on the size of the craft, it can even carry a self-righting bag, but in most cases this steel frame is just a glorified mast.
A-frames do much to enhance a RIB's appearance, and come in powder-coated or stainless steel. Many divers will also have brackets attached to the upright sections of these frames to house storage poly-bottles, useful for keeping small items dry and protected, and excellent emergency grab containers for flares, a hand-held radio and other useful items.
Consider your needs carefully. How far offshore will you be journeying and for how long will you be at sea? How many divers will you be carrying? Most RIB builders who supply the dive market offer a degree of customisation and even cabin options, so establish which company appears most interested in your needs.
Find out what warranties come with the boat and what the aftersales support is like. Ensure that delivery times, payment terms and warranties are all carefully documented. Check the insurance, and remember, to carry other divers for reward, your vessel must comply with the necessary coding.
The MCA and DTI have the details.
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| A RIB's inflatable sponsons provide huge lateral stability both underway and at rest. |
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| Storage for cylinders can be provided by means of stainless racks or these grp bottle-holders. |
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| Poly bottles are useful storage additions to the A-frame on this Tornado. |
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| Though care should be taken, it is possible to beach a RIB for disembarking or loading heavy dive kit. |
The show dedicated entirely to RIBs takes place this year in Cowes on the Isle of Wight, from 11-14 May. RIBEX is a unique waterborne show that affords visitors an unrivalled opportunityto carry out full sea trials of some 70 RIBs, and so compare boats and engines back to back.
Besides the on-water exhibits, products of every type, including engines, chandlery, electronics and specialist equipment are exhibited ashore in the tented village overlooking the event marina.
The show is the ideal one-stop opportunity to find the full spectrum of RIB-associated products.
With a full programme of displays and interactive events each day, RIBEX is also a great day out for the family. If you want to find out more, visit www.ribexhibitions.co.uk
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Avon Inflatables - www.avonmarine.com
Coastline Marine - www.coastlinemarine.co.uk
Delta Power Services - www.deltapower.co.uk
Humber Inflatable Boats - www.ribworld.co.uk
Manning Machine Tools Ltd (Osprey Boats) - www.ospreyribs.co.uk
Ocean Dynamics - www.ribworker.com
Red Bay Boats - www.redbayboats.com
Ribcraft - www.ribcraft.co.uk
Tornado Boats International - www.tornado-boats.com
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