February1997
The amazing shrinking RIB
Ever wanted a RIB you could put on your roof rack? Well, here it is: the Craft Espace folds down so small you can even put it in a car. Dag Pike puts it to the test, while John Bantin looks at a new BC, a line reel and the latest radio-linked dive computer.
One of the attractions of the inflatable was that it could be deflated and folded up into a small space. Then came the rigid inflatable. You couldn't fold it, but it was a much more seaworthy and durable boat. Now the wheel has turned full circle and we have a rigid inflatable that can fold up.
The unique Craft Espace was developed primarily for the yacht tender market, the aim being to produce a boat with all the attributes of the RIB but which could be dismantled and stowed on board easily, for security on long passages.
This application reflects the background of the man whose brainchild it is, top yacht designer Rob Humphreys. But a potentially larger market exists among divers who want a car-transportable boat without the pain of towing a trailer.
The Craft Espace is 5.4m long with a beam of 2.28m. But it folds down to a package of 1.8m by 1.8m by 0.53m, which can fit inside a large car or even be carried on a strong roof-rack. It offers freedom of use, particularly for divers who want to take their boat on long journeys to a new diving spot.
The rigid part of the hull is made in three sections, each of which will float independently. The flanges between each section form the transverse stiffeners for the assembled hull and also the connecting link between sections.
As the flanges are brought together, they are connected by a series of stainless-steel bolts, which are simply fitted into drilled holes and tightened. There is no need for seals because the flange extends to deck level and prevents water entry.
The hull can be assembled afloat if necessary and by one person, though it is easier with two.
The open tops of the hull sections are covered by panels that slip into place and seal with rubber joints. These panels provide the mounting point for the consoles and seating available with the Craft Espace.
The inflatable tube, a one-piece fitting in a neoprene/hypalon-coated fabric, fits on by sliding a shaped fabric flange into a moulded groove around the rigid section of the hull. The tube is further
secured with rope lashings fore and aft.
The hull can be assembled in half an hour, the makers claim, though this sort of time is likely to be achieved only in ideal conditions, and once the owner is very familiar with the assembly process. Dismantling it would generally be quicker.
Advanced composites are used to create the necessary strength in the flange areas, but they also help to reduce the weight of the hull, so that the heaviest section weighs only 60kg. The whole boat, including tube and console, weighs 180kg, little more than half the weight of a conventional rigid inflatable.
The use of hi-tech materials to keep the boat's weight down is fine out of the water but is reflected in its performance in the water, where it becomes more sensitive to waves.
It also pushes up the price when compared with a rigid RIB - it costs £17,331 including VAT. However, money can be saved because less power and hence a smaller motor will achieve the same performance as with a heavier boat. And you save on the trailers!
The recommended outboard is a 50hp unit and on the test boat the 50hp Tohatsu produced a speed of around 30 knots.
The hull itself is a deep V with two spray rails on each side and a pronounced chine. The air tube is mounted high on the hull, so the boat has to heel over about 10* before it touches the water. This makes it very sensitive to weight distribution at rest, and it feels "tippy" when stepping aboard.
Once under way, the dynamic stability of the hull comes into play, giving the boat conventional deep-V hull performance. The high tube mounting ensures a dry ride, with spray coming over only when there is a fresh wind on the bow.
Handling is very positive and the taut steering allows the boat to make tight turns securely. In head seas you become conscious of the full bow sections, which tend to accentuate the pitching, but the performance in following seas more than makes up for this, with the bow lifting cleanly over a wave. In both cases, sensitive use of the throttle produces good performance.
The steering console is a simple stainless-steel structure topped by a glass-reinforced plastics moulding that creates the dash, and the wheel and throttle mountings.
The portable fuel tank sits on the deck in front of the engine and the open battery stowage is under the steering console with the basic layout, but with the saddle seat fitted, there is enclosed stowage underneath for these items.
Self-draining points are fitted in the transom, and with the deck well above the waterline no water lies in the boat when it is moored. The builders offer an air-bottle rack to fit into the stern.
Craft Espace, 01590 679344.
Easy winder
THE KIND of small winder reels used for cave diving tend to be made of a robust combination of metal and perspex, and are now finding favour with technical divers.
This 9cm diameter reel, new from ALS Marine, is made from heavy-weight perspex mounted on a chassis of 8mm, 316 stainless steel rod, which is bent and welded into shape. The reel assembly distinguishes itself by having no nasty edges on which to hurt yourself when winding in the line.
It is a simple enough bit of kit. The winding handle and locking knob appear to be hewn from a piece of resin, and nylon-centred locking nuts make sure the whole thing does not fall to pieces when in use. It comes with around 50m of 2.2mm line which feeds through a line guide. I found it to be a high-quality item, which was easy to use and left me with no knocked knuckles. It costs £49.95.
ALS Marine, 01797 227185.
Italian splash of colour
BRITISH DIVERS apparently lack any sense of style. Particularly among wannabee technical divers, black suits, black BCs, and otherwise shabby gear seem to be admired as a form of dress. Is the activity of diving to blame, or is there an innate British inverted snobbery concerning personal appearance?
Clearly, the Italians do not share this philosophy, as indicated by the new Mares Syncro Pro BC , which brings a little continental colour to the diving scene.
The Syncro Pro is a conventionally designed item - a single-bag design with useful, well-drained pockets, a hard back-pack with a single cam-band, and an adjustable cummerbund. However, the cummerbund did not seem to be very extensible, so I would hesitate to recommend this jacket to a person of portly build.
The size I was given fitted me with a wetsuit, but, as with many other conventional-style BCs, I found that it tended to ride up higher than I would have liked. Also, I doubt if the cummerbund would have been long enough had I been wearing a drysuit.
Air is injected into the jacket by an attractively designed direct-feed mechanism, and is dumped by way of a shoulder dump on the corrugated hose. There is another dump at the lower back which serves as a water drain or for use when inverted.
This BC gives plenty of lift for someone using a single cylinder and a wetsuit. Shoulder straps run inside broad epaulets and all buckles exude quality with a smooth finish.
The Mares Syncro Pro is available in sizes S, M, L, and XL and costs £285.
Blandford Sub-Aqua, 01923 801572.
Radio link on air
DECOMPRESSION computers are getting more and more sophisticated. Recently we have seen the advent of hoseless air-integrated computers (connected by radio signal), notably those introduced by the Swiss company Uwatec and cloned in various guises. The new Oceanic DataTrans is a US version of the same technology.
The DataTrans keeps an eye on how much nitrogen the user is absorbing, indicating remaining no-stop times or required decompression stops. In addition, air integration enables it to estimate how long the air remaining in the diver's cylinder will last according to current depth and preceding usage.
Combining these two sets of information should go most of the way towards ensuring that no diver runs out of air through poor air-management. The hoseless radio link enables the display unit to be worn conveniently on the wrist.
Like its European rivals, the Oceanic DataTrans comes in two parts - the transmitter unit, which fits on to a high pressure port of the regulator first stage, and the wrist unit, which displays all the information required.
Both units are powered by batteries which are easily replaced by the user. The transmitter, which is automatically turned on when it senses cylinder pressure in excess of 3.5 bar, uses three shirt-button silver oxide batteries. The wrist-mounted display unit uses a small lithium cell. Both should last for about a year of normal diving.
The instruction manual at first seems rather daunting. This is because the manufacturers have allowed the user so many options.
These are set by means of two pushbuttons, which you press to set mode and sub-menus. There are 13 different operational modes including surface mode, planning, dive log, complete unit history, external access and setting mode.
You can use this last one to opt for figures provided in either the imperial or metric system, and can choose written information in any of five languages. You can set a clock with the time, day and date.
Predetermined alarms can be set for a chosen maximum depth and for a reserve of air from 21 to 70 bar, without needing a separate PC and interface. You can also turn off the audible part of the alarm system.
The display unit can be linked or unlinked from the transmitter, for those people who prefer to buy the transmitter unit at a later date.
Once you are ready to go diving, you have to turn on the wrist display unit by pressing the "select" button, unless the computer is still calculating residual nitrogen levels from a previous dive. I have to confess that I forgot to do this at least once.
However, if I had not been using the DataTrans alongside another air-integrated computer, I would have noticed that it was not switched on when I came to check my cylinder air pressure.
Once switched on, the screen is loaded with information. It indicates remaining cylinder air pressure and current depth. It shows remaining air-time in the form of a reducing bar graph allied to a green "more than ten minutes" zone, a yellow "less than ten minutes" zone and a red "less than five minutes" zone.
It also shows increasing nitrogen absorption in the form of an increasing bar graph next to a scale which shows a green no-stop zone, a yellow caution zone, and four red zones representing ceiling stop depths. In addition, the remaining no-stop time or remaining air-time is shown in the largest numerals in the display.
If you hit decompression stops the computer warns you with the word "Ceiling", and displays an icon showing the total decompression time required. To find out the actual stop depth and time required, hit the "Select" button. If you are still into no-stop diving, this will give you water temperature, maximum depth achieved during the dive, dive duration and even the time of day.
The other button,"Advance", activates a very effective display backlight, which is invaluable in poor visibility or at night.
Two other bar charts are allied to green, yellow and red zones. One regulates your ascent rate from a very slow 3m/min to a fast (red zone) 28m/min. When you enter the red zone at 19m/min, the message "Too Fast" appears on the display, but I never got to see it!
The other bar graph indicates air consumption. This did not seem to represent any tangible breathing rate and, of the eight possible segments, I never got more than three to display.
Audible alarms are grouped by urgency. Single beeps indicate entry into decompression mode, while continuous beeps might indicate ascent-time longer than air-remaining time, or air-remaining time equalling zero (plus predetermined reserve). The message box in the display offers an ongoing explanation.
After diving, the DataTrans displays time-to-fly in two 12-hour segments to allow you to choose your own degree of safety. This will depend on the sort of diving you have done, type of aircraft and altitude.
Despite all the options, I found that the information this computer gave me was not much different from that of the European counterpart I wore mounted on my wrist alongside it.
The decompression mode used is based on the no-decompression multi-level repetitive dive schedules tested by Rogers and Powell in the USA. Because these tests did not include repetitive dives deeper than 27m, the decompression predictions of the DataTrans are based on information from the US Navy. The DataTrans tracks 12 tissue compartments with half-times from five minutes to eight hours.
The display unit measuring 8cm x 9cm is a little larger than some others, but I found it eminently readable and it had a strap long enough to go around the wrist of my drysuit.
The DataTrans costs £554.
Oceanic, 01404 891819.
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