I need a module which can be used to display ships for sale. Companies can come to the website, register with it and then add their ships that can then be displayed for sale. The module needs to have the ability to add details fields.

An example of what I am looking for is
http://www.shipsaleandpurchase.com/search_ships.aspx

On this page click search, it displays all ships with their type. Click on details gives the complete details and then one can use the contact link below to contact the site admins for that particular ship.
Kindly suggest

Olédrion used as catalog mode has got these features... and more.

110% recommended!

or you could take a look at classified ads module (there are two, I believe. A paid for version by InstantZero, and a free one from JimZone)