I am making a New York Yankees logo and need to get that navy blue color. I added one part violet to one part sky blue...it does not look navy blue!! Please help...cake due tomorrow

Add a little black.

The black should help plus it might darken by tomorrow too.

Here's a couple of charts:
http://www.wilton.com/decorating/icing/icing-color-chart.cfm
http://www.cakecentral.com/cake-decorating-ftopict-589750-navy.html+blue

Thanks guys!! What I did was add a little royal blue and lots of black. It ended up looking a dark navy blue just the color I needed. Hopefully, it looks for tomorrow Thanks girls for all your help