Hi. New to boating. I am looking for a boat 16ft-19ft to be used in both salt and fresh water for fishing as well as just cruising up the river. I would like it to hold 4 to 6 people, if possible. I want it to be economical so I assume an aluminum boat, being lighter, would be the way to go as it would only require a smaller motor. However I am hearing negative things about putting an aluminum boat in salt water;issues about corrosion. I do not plan to moor the boat in salt water, or fresh for that matter. It will be trailered to whereever I launch it. Is this aluminum in saltwater something to be concerned with? If aluminum is okay, is welded much beter than riveted? Are the newer 4 stroke engines better than 2 strokes? I have been looking at the crestliner "sportsman" and "canadian" models and they seem pretty good however, I have never owned a boat so I don't know much at all about them. Any feedback would be surely be appreciated as i do not want to buy a boat only to find out that it is not what I really wanterd. Thanks, Al