If I start out with fishing and seafood, I like to build workboats first to let my city grow. However, since workboats are one-use improvers and workers can build multiple improvements each, I'm worried that this strategy is wasteful of precious early-moves time. Is it?
Ah, come on a4phantom, you know the answer for this one. It's the civ4-answer for everything:
![[party]](/images/smilies/partytime.gif "Party [party]")
It depends! 
Hmm, maybe I can say something more useful, but it's really hard to make general statements about what to build at the start of the game. So I'll give you some advice which may help you make your choice between worker and workboat.
-You can count a bit to see what is the best option. Really counting 40-50 turns in advance is maybe a bit hard and boring, but in the end it's the way to find the optimal path. But of course, you can't predict the effect of tech advances from goody huts, so even counting has its limits.
-Take a look at the technologies that you need in order to improve the terrain. Do you need animal husbandry and you don't even have the prerequisites, then starting with a worker doesn't seem wise. If you don't start with fishing, then you can't even build a workboat.
-If you start with a city that can produce 4 or 5 hammers per turn (plains hill starting position and/or a forested plains hill to use) and the ability to build workboats, then you can get a workboat in about half the time that you'd need to build a worker. Working an improved resource tile is very efficient so if you can do that in half the time by building a workboat instead of a worker, then that is almost always optimal.
edit: On the other hand, if you start with a city that has a very low hammer output of say 2-3, then the workboat improvement will not be finished significantly faster than the worker improvement and the advantage of the worker that can potentially construct multiple improvements (depending on terrain and technologies available) is significant.
-If you don't have enough improved tiles and you plan to build a workboat, then get it finished as quickly as possible. Don't try to combine growing with constructing the workboat. Get that workboat as fast as possible. You want to use improved tiles.
-Building a workboat and then using this improved tile can dramatically increase the speed with which you build workers and the speed at which your city grows. A fish tile is a lot better than a crab or clams tile, a 5 food tile is a lot better than a 4 food tile. You typically have lots of 3 food+hammers tiles in your fat cross. A 4 food tile is a small improvement, a 5 food tile is a far more significant improvement. (I'm assuming no lighthouse as it takes a while to construct this building.)
-If you start with mining and thus the ability to directly research bronze working and you are in a situation with several forested tiles in your BFC, then building a worker and chopping the workboats can be very efficient. Instead of improving a farm tile with the worker, you're effectively building the workboat with the worker actions. Bronze working also immediately gives you the option to use slavery and thus convert the high food output of seafood into hammers.
-Seafood is not only good because it increases the food output of your city, but it also improves the commerce output of your city. Using 3 coastal seafood tiles almost doubles your commerce output early in the game. This can be great to develop other important early game technologies.
-Don't improve more seafood tiles than you're likely to use early in the game. When your happy cap is 5 and you plan to use an ivory tile and a corn tile, then you don't want to improve more than 3 seafood tiles (that's a great theoretical city by the way).
My favourite law 
