Brendan - I can't get over how seemingly noise-less your photos are at ISO 1000. Cohteteboy - Same with your 800. Those are just really, really clear. I don't know if I've been able to push my ISO that high without the noise showing up. I'll have to check.
As for Leslie's original question, I think it will be a challenge to get decent shots in Pirates with less than a 1.4 or 1.8 lens. Dlandjimmy had a 1.8 on his shots above, and it really does make it easier to walk away with a great shot if you don't have to push the ISO quite so high to get the shot. The fact that you are constantly moving and getting bumped into makes it tough to slow the shutter much below 1/100, but every once in awhile you can manage to get a shot off without the boat lurching. If you have a very steady hand, you can get by with much lower shutter speeds. (I drink WAY too much coffee for that to work for me. )
And I'll second the Gorillapod suggestion. It's MUCH easier to manage than a tripod if you are going to be there all day.
Leslie - If you shoot many shots out in the bright afternoon sun, you might also think about a filter. I just bought a circular polarizing filter and tried it out, with varying levels of success, last Friday. I was constantly having problems with blown highlights in very bright sunlight, and with the hazy, butt ugly haze that is usually burning off in orange county in the morning, my skies tended to be rather ugly as well, hence my need for a filter. I haven't decided how much I will shoot with it yet, but apparently, it works the best when the sun is directly over head...or so I've been told. My skies came out much bluer and the rest of my colors popped a bit more. So...just another option there.
And Robotmirror... Love your shots. Any time that you want to start posting again, please feel free. We miss your photos!