Hi Steve18.
This has been already discussed lots of time before.
You can use whatever combination of joysticks you want. There's no specific joystick for ship simulator now, but Rail Driver plans to release one, announced for "early 2009" : http://www.raildriver.com/products/shipdriver.php
Keep in mind that today, no joystick set up can be used for azimuth propelled ships (Ocean Star and Bugsier), and a good keyboard config remains - imho - the best solution.
regards !
Denis