Originally posted by bam1515 ...My question is how do I shoot them swimming without the blur and getting a great shot?...
Indoor sports are a challenge. Blur-free action shots require a high shutter speed. You need a lot of light, high ISO, or a bright (aka "fast", wide aperture, low f number) lens. I assume they're swimming indoors so it's not very bright. The ist is an older camera and you can't crank the ISO very high without introducing too much noise. A superzoom like an 18-200 tends to be a slow lens. This means you have all 3 elements working against you.
You
might have to upgrade equipment but maybe you have enough light to work with. Experiment with shutter speed 1/250 or 1/500, ISO 1600, and wide open aperture. Check to see what you get. if you need more light push ISO to 3200. You might have to shoot in raw rather than jpg to process out noise later.
If all of that doesn't work, then you might need to upgrade your camera (newer models offer higher ISO) or lens to something like a 70-200 f2.8.