Also the LOD tricounts are really fluid and the only thing that matters is that the switch between LODs is as imperceptible as possible, and that the switching distances between the LODs are reasonably big; it's a waste of time to build a LOD which will only be used at a very narrow distance range.
The last LOD can be a blob of a handful of polys as long as the distance at which we can switch to that is useful; there's no point in having a LOD that we can switch to only when the ship is 20km away because that practically never happens. Better to have a blob of a hundred polys that we can switch to at 5km, because you often see ships that far away.
So, it really depends on the distances. I'd suggest trimming away as many polys as you can while keeping the change (almost) imperceptible at "medium distance", then the next LOD at "long distance" and the final one at "barely visible" distance. I've attached a quick sketch of how I'd approach it, but this is by no means a set of specs you must follow. I'm just writing this stuff down because I don't think I have before.
[attachment kidnapped by pirates]