Rough water handling in a RIB - part 1
by Paul Glatzel
In the same way that Land Rovers appeal to those who just drive off-road in Tesco's car park as well those keen to wallow knee deep in gooey mud then so too RIBs are bought both by those who just like and appreciate the styling and the ease of use but also by those keen to test them a bit in the conditions they were designed for.
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Ploughing through a head sea
As you would be ill advised to take a Land Rover into conditions you have not been trained for then so too taking a RIB into conditions that test its capabilities is foolhardy without both knowledge and experience. The reality is though that RIB owners will tend to push the boundries of their boat's capabilities more than the owner of a typical sportsboat would, RIBs tend to be forgiving and perhaps imply a sense of immortality that is neither warranted or sensible. Because RIBs tend to go out in rougher seas then it is more likely that they experience conditions that will test and endanger the crew, so knowing what to do makes sense - hence these articles.
In the first article we will address the more typical conditions and problems faced by RIBs. In article two we will look at more extreme conditions such as how to cross a bar and the dangers of a following sea.
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Up and away again, back on top of things
But why are RIBs better than the average sportsboat at handling tough conditions? The RIB (Rigid Inflatable Boat) evolved from the simple soft bottomed inflatable as a means to reduce hull wear when dragged across a beach. In time the hard bottom evolved into the deep-vee we see today and the RIB as we know it was born. The combination of this deep-vee and the tubes (sponsons) give a RIB its outstanding sea-keeping qualities.
The tubes act as shock absorbers taking a high percentage of the impact on the boat thus reducing the stress on the crew. Lateral movement is also reduced significantly giving a far more stable ride than other types of boat. This sea-keeping ability means a RIB can handle seas way beyond what other types of boat of its length could handle, its ability to both not to take on much water but at the same time to be able to get rid of it quickly if necessary - via a low transom and 'elephant trunks' and the like - really do denote a very special type of boat.
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Keeping the power on, cutting through an awkward choppy sea
When helming any type of vessel the key is to try to match your speed and direction to the conditions through careful control of the throttles and steering. Jumping from wave to wave, or ploughing through waves can be great fun but your crew, you and the boat will find it very wearing very quickly. Indeed on the recent RB4 (Round Britain in 4m RIBs) 'race' numerous boats experienced failures of their engine mounting brackets because of the stresses placed on the boats.
There are a variety of conditions you will need to master driving in even fairly moderate seas. Driving upwind ('to windward') typically means driving up the face of the wave then easing off at the top to ensure you don't take off, then driving down the wave speeding up to raise the bow as the next crest approaches. The ride thus becomes smooth and quite fast. As you can see progression here is about throttling 'on' & 'off' as you move through the wave.
Whether this proves to be a comfortable ride depends to a large extent on the 'wavelength' (the distance between the wave crests) as shorter wavelengths can make it very difficult as there becomes very little time between wave crests for the helmsman to adjust the throttle settings. In this case you might find it easier to drive at 30° - 45° to the waves. This increases the 'apparent wavelength' and can therefore allow you to increase your speed and smooth your journey. You will then need to zig-zag towards your destination but whilst longer in distance terms it will be less stressful and arguably quicker.
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Heading out through the confused seas around the Needles
Whether proceeding at an angle to the wavefront or totally perpendicular (a 'beam sea') to it you must remain very aware of breaking waves as they have the potential to capsize the RIB quite easily. In 'beam seas' you can attain a fair speed as you drive constantly watching for breaking waves and steering a path behind or infront & away from them as conditions dictate. Here the speed and power of the RIB is key, if your vessel isn't capable of powering its way away from trouble then it is not suited to the conditions.
In this article we have looked at some fairly typical conditions. Whether ploughing into a head sea or running at an angle to the wave front the key is vigilence and actually 'driving' the boat. Driving is not 'power-on and head in that direction' it is about adjusting your speed & direction according to the conditions, perhaps using less power to attain a greater speed, it is about 'reading' the waves and steering accordingly. One last thing, just remember that if you ever scare yourself then you will have petrified your crew, don't forget that you have the luxiury of a steering wheel and throttle to grip onto, their 'handhold' is their trust in you!
In the next article
Paul addresses how to tackle following seas and crossing harbour bars.
Paul Glatzel is an Advanced Powerboat Instructor and runs Powerboat Training UK - www.powerboat-training.co.uk
- 01707 322789
© Copyright Paul Glatzel 2001. Photos courtesy of Scorpion RIBs.
This article was first published in Sportsboat and RIB Magazine.