A recent development in hovercraft technology has enabled the growth of a family fun activity that just hasn't been available before. After the jet-ski fad, and quad bikes, we now have the exciting prospect of floating around on our own personal vehicle. Younger people love getting their thrills for fast machines, and hovercraft are no exception, but as we get older there are other considerations that become more pressing. Racing around when a teenager is great and necessary, but when we have a family, and thinking to buy four seater hovercraft our protective instincts kick in and we look for an altogether different experience in our fun time together.
Air cushioned vehicles might look pretty harmless, but they have to be treated with respect, just like any other device that can hurtle you along at up to 60km an hour. There are no wheels to hit obstacle on the ground, and it doesn't fly high in the air, so no danger of a fatal crash if power is lost, but there are a couple of things to consider that other means of transport just don't have. Most of the smaller hovercraft are turned by moving a set of handle bars, like a motorbike and simply throwing the body weight over to one side. As the only contact between the vehicle and the ground is air, then the reaction time to operator control is delayed.
For this reason, anticipation is key to successful operation, and very important if you have the family on board. The manufacturer will specify a maximum weight for your passenger load, which should not be exceeded. The load given may seem quite light, but an unfortunate fact is that it takes much more lift power to get a loaded craft off the the ground than to keep it hovering over the ground. On water it's even worse. Lifting off from water is called 'getting over the hump' and it's a particular problem for the design team.
Perhaps the most serious safety factor for a small vehicle is the phenomenon of 'plowing in'. This is when there may be waves when traveling over the surface of the sea which come into contact with the bow of the craft. A poorly designed hull and skirt arrangement can cause the whole assembly to dip into the water, with disastrous consequences. Imagine flying at 50km an hour and the front just drops and meets a solid wall of water. The occupants and everything not tied down would just be launched forwards, which is obviously a very bad situation for people, and particularly children.
Most countries have one or more services funded by the government or by the public, which provide help for people in danger from natural disaster or other kinds of life threatening accidents. Such services have a variety of marine and land vehicles at their disposal, and depending on their local environment. Air cushioned vehicles, or hovercraft as they are commonly known, can provided a flexibility not matched by other modes of transport.
Imagine a plane crash somewhere over the Russian steps. Thee weather is bad and the visibility over 1000 feet is very bad, with strong gusting winds. The terrain is sometimes frozen and sometime marshy, making it very difficult for a wheeled vehicle to navigate. A helicopter couldn't get close in those conditions and ground vehicles have been ruled out. Why not use an ACV that floats about a foot over the ground? Marshy and icy surfaces mean nothing to a vehicle that rises above them, so it's a perfect choice.
Many locations are next to lakes or large bodies of water. Of course, rescue operations for these locations will already have boats ready to do the job, but what about a northern clime in winter time? A boat would simply not do the job in the northern end of Lake Michigan when ice covers much of the surface area. In this situation, a hovercraft would be ideal and many rescue team leaders are starting to realize this and more than makes up for the cost of buying a hovercraft
Survey exploration of vast territories is another situation where an air cushioned vehicle can perform well. It's not sure that any studies have been done to ascertain the economic virtues, but it's certain that hovercraft manufacturers will have the right information to hand. Marine craft and small boats tend to use two stroke engines, which run on a mixture of petrol and oil. In this way, they don't need a separate oil reservoir, so there is a small cost saving here. On the downside, they are less smooth than a four stroke engine.
The four stroke petrol engine is generally quieter, particularly if water cooled, because the engine is surrounded by a water jacket. A powerful four stroke motor can easily provided both upward and forward thrust through a system of ducts which separate the air flow to the area under the skirt and behind the craft. Larger hovercraft would need more than one engine of course, but a small single engined version could rapidly travel to an accident site and bring back two or more accident victims.