Long exposures, anything with a bit of movement

30 seconds f6.3, used a head torch to paint in some detail, hence the vignette effect

You could use them if you wanted to work before it got too dark though (or light), but then you will have the problem of exposure altering as the sun sets (or rises). And maybe vignetting if you need to stack them.

No, it's dark so no need.

Are you using neutral density filters?

I look for the best camera position I can find during the day, it's very hit and miss otherwise. bear in mind the tide conditions if your really near the shore. Then I turn up with a sturdy tripod and a cable release, I have a cheap remote one so I don;t have to touch the camera (best during long exposures). Then I'll fire off a couple at something like f11 and 10 seconds and adjust exposure from there based upon the histogram.

I try not to go over 30 seconds especially if there is any wind. Plus I would then have to then control the exposure length manually anyway and I'm lazy.

Always shoot in RAW and at 100 or 200 ISO

How about some details on to how to take the sea shots?

Just did a quick search in my aperture library for slow shutter speeds, pretty cool that you can search EXIF data. Came up with these.

Great atmosphere - you expect Gollum to leap out from a rock to find his ‘precious’