Hi landman, and welcome!
Do you mean in a mission?
You need more than one player ship for that. If you have two ships in the mission (or more), you can switch between them.
Hit F3 to open up the player ship icons in the upper left corner, and click on the icon of the ship you want ot transfer too.
So you can run them at the same time, and thus sail next to yourself, if you wish.
I hope that answers your question.
And as you're a new member, perhaps the following links might help you find your way around;
The Help Page. To assist you with forum posting, and the more advanced features on the forum -
http://www.shipsim.com/ShipSimForum/index.php?action=help
The Forum Rules. To help you make informed decisions regarding posting - http://www.shipsim.com/ShipSimForum/index.php/topic,26.0.html
The Posting Guidelines. These will help you determine where to post about a specific subject -
http://www.shipsim.com/ShipSimForum/index.php/topic,11578.0.html
The Search function. A very useful tool to help you find the answer to that elusive question -
http://www.shipsim.com/ShipSimForum/index.php?action=search
The Tutorials board. Check here for guides that cover common questions -
http://www.shipsim.com/ShipSimForum/index.php/board,35.0.html
The Technical Support board/s. Got a problem with your game? This is where you need to check first.
Ship Simulator 2006 Technical Support -
http://www.shipsim.com/ShipSimForum/index.php/board,9.0.html
Ship Simulator 2008 Technical Support -
http://www.shipsim.com/ShipSimForum/index.php/board,5.0.html
* Please note: To access Technical Support, you will need to register your Ship Simulator licence key into your forum profile. If you're not sure how to do this, please check the General FAQ's, or send a Personal Message to a Moderator.
The FAQ's and Announcements board. Check here for answers to commonly asked questions. Also a useful source for the latest information regarding Ship Simulator development - http://www.shipsim.com/ShipSimForum/index.php/board,1.0.html
Any other questions you have, the Moderating team are always on-hand to help you. You can contact any member of the team by Personal Message.
Happy sailing!!
Regards,
Fred