I'm very interested in getting a side scan machine. There's a hitch though....I don't know anything about them except for the images I've seen online. What I would like is a SSI model that I can mark the tagets on a GPS/chartplotter and also record the images onto a cd/dvd. I'm assuming that there is a Hummingbird model that can hook up to a laptop??? What Hummingbird models could do this? Which one is the most for the money invested. I'm looking for things as small as a 15 ft skiff in 60ft of water and as big as a freighter in 400feet of water. I really need a good book on how these things work. Looking at Hummingbirds website I can't compare features because I don't know what they are talking about. any advice is appreciated.