If you're going to make Die Hard on a Boat, I only ask for a few things.
1. The actors need to be having fun. Commitment to the part.
2. The violence needs to be bloody and merciless.
3. The violence needs to be undercut by humor.
4. The hero needs to be an everyman but still kick incredible amounts of ass.
5. The action scenes need to vary and escalate the plot.
6. Your team of bad guys need to be distinct, so if you cast Tommy Lee Jones, Gary Busey and Colm Meaney, you've exceeded requirements.
7. One-liners. A good one-liner can elevate a poor scene and convince you it was a good scene.
8. Brevity is king. No action movie should be over two hours.
Under Siege is no Die Hard. It's not even close to Speed, but it meets the above criteria and is therefore a fun movie.