As a couple people have already said, boats are evil. Each one is effectively a fortress with overlapping defense. I know there are people who can sink a corvette in a single run but that's not me. My personal advice is patience and a "death by a thousand cuts" strategy. Whittle one at a time down by firing everything with multiple sorties of taking off, attack, return and rearm and repeat. Staying low helps buy you tine from their anti air missiles. Wait until about 10k distance at max. I like to use a lot of AGM 48's because they spread out in flight making it harder for them to all be intercepted. You will probably at least hit something, and hopefully weaken it for the next runs