My SH3 also had a lot of crashes at first. The kernell crash has something to do with lack of RAM memory IIRC. Installing the Lite Harbor Traffic mod did the trick for me. It made my whole game run smoother, not only when I'm near a port. I didn't think it would make that big of a difference but it did for me... I'm not saying that it will solve everything for you, but I recommend you try it
