The Tow Tank website is: towtank/www/index.html
The site is hosted in the AFS locker 'towtank' found at /afs/athena.mit.edu/org/t/towtank. You can access it by logging into athena as yourself and then modifying the files in that directory. Any member of the moira group towtank-www can edit the site. You can check if you are a member through the moira interface: https://groups.mit.edu/webmoira/. If you are not a member and would like to update the website, ask Maria to add you through the moira interface.
You can access the locker either at an Athena workstation or through ftp: https://ist.mit.edu/software/filetransfer. MIT provides software for ftp (Fetch for Mac and SecureCRT/FX for Windows). You can follow the instructions at the link to access your athena account through ftp. Once you have navigated to the locker, you can either download the files to edit them offline, or edit them directly. The current website is in a very basic format (html pages which can be edited in any text or code editor). The main pages you may want to edit are 'people', 'research', and 'publications'. It is fairly straightforward to copy the format existing in the files to add new items.
Feel free to make changes, redesign the website, and have fun!