There has been a weird issue in the latest client version, in which sails in offshores appear to be invisible. This is a huge issue in instances like EC at which players have to know the color of ship sails in order to avoid killing them.
Several people reported this issue before:
Ship sails appear to be invisible in offshores: http://vc.forum.igg.com/topic?fcid=59&ctid=58108
Ship sails appear to be invisible in offshores: http://vc.forum.igg.com/topic?fcid=59&ctid=57345
Here is a small patch that solves this issue. Installation guide and download link can be found below.
Windows 7 installation guide
0. Before proceeding, make sure the game is closed, otherwise you might receive various errors trying to install.
1. Download the .zip file from google drive link found in this post.
2. Right click one the .zip file, click on Open with and then on Windows Explorer.
3. Once a new window opens, click on Extract all files button which is located at the top.
4. A new window will open that will ask you where do you want to extract these files. Click on Browse and locate your Voyage Century Online folder. After your found your folder, click OK.
5. Uncheck the Show extracted files when complete button.
6. Click Extract button.
7. A new window will open, telling you that destination already contains a folder with the same name and it will ask you if you want to replace it. Choose Yes or Copy and Replace as many times as it asks you. Please not that if it doesn't ask you, then you most likely got the step number 5 wrong!
I've tested this on 2 different clients, it worked both times. Please feel free to report any problems.
Do not download this fix from any other sources except the one listed in this post!
Check out various tools for VCO at The Pirate's Cove: