Some of the important features of personal hovercraft to check before sale are visible to the naked eye and some are not. Others can be tested while looking around the craft, while others still need the craft to be moving. The last category you'll have to take the manufacturer's word for, and so you'll be depending heavily on their reputation and whatever information you ca glean from previous customers - the net is great for this kind of thing. Let us imagine that you're walking up to anew hovercraft and you know absolutely nothing about the industry. What questions should you ask and what should you look for?
We should assume that you've done a minimum amount of homework and are generally happy with company's reputation - you now want to get your hands on an ACV. First of all, do you like the look of it? Just like a car, you need to find it agreeable because you'll be using for quite a while. Take a look at the fittings and fastenings. It's pretty easy to see bad construction and it's mostly the little things that can flag up possible problems. If there is a screw missing from a safety handle, then it's possible that other screws are not too tight and could give trouble later on.
Show the sale person that you know a bit about the subject of hovercraft performance and design by asking about how good ti is at 'getting over the hump'! This is the term used in the industry for the ability of air cushioned vehicles to life off from water, which normally requires up to 300% of floating power to achieve - good explanation here. Helicopters take up to three times more power to lift off than a hovercraft needs to hover, so this feature is a great indicator of performance.
Next, it's an absolute must to ask about the reaction of the craft to the phenomenon known as 'plow in'. This can happen in choppy seas, for example, when waves are constantly lapping up over the bow. In certain circumstances the bow of the hull can be pulled down into the water with disastrous results. Basically, it comes to a full stop, throwing everything that isn't fastened down over the front of the craft. Even if passengers are well strapped in, there is still real risk of injury.