for a Mac, use Sail Replay, its free

For Windows, Boat Scenario - http://boats.sourceforge.net/ , also free.

Another one is Tactical Sailing Situations, but it's 40 Euro and the author has passed away (no more support).

True, TSS is not being updated, but in its current version, it is a pretty good program.
Most, if not all of he diagrams in the Match call book are done in TSS.

For Linux also boats: http://boats.sourceforge.net/

Nice, thanks you all. Downloaded Boat scenario, looks good. 
Cannot draw a boat sailing by the lee, anybody can give me a hint? 

To change the sail to by the lee - hold down Shift and press either . (Period or full stop) or , (comma)

1. create a boat:  (under Edit in menu, or the icon with more boats), click= boat in 1st position,  move the mouse, release the boat by double click. 
2. Edit the position and  heading of the boat : (kursor on the boat+press and hold the left button to move the boat, or right mouse button+ move the mouse to change heading, release the button, when heading is OK)
3. trim the sail ( click on the boat (outline turns on to red) and by  "<"  or " >"  you trim the sails. (usually need an "AltGr+< " ) ,  or if you clicked on the boat-  go to menu Edit, or right click ( -> window with tools)

To Robin Gray

What programme is that for?

Hi Criag - That was for Boat scenario

Is there any diagram makers, that is compatible with protests held on Zoom?
 

Magnetic boats and a white board.

You're going to have a new one in your pocket! The new US Sailing Rules app has a "whiteboard" for protests. It's fiddley at present but a lot of the other tools are too.  iOS and Android I believe, and probably better on a tablet then a phone screen 

Craig, I managed to drag a boat onto the grid .. but how does one rotate it?  I saw that double-tapping enables changes in sail trim. - Ang

I'm hoping it gets updated it's not intuitive coming from a mouse and keyboard program.  
pinch and drag to move and zoom on the water, 
to rotate a boat: 1 zoom in on it pretty far first, use two fingers to rotate it.  
You already discovered the sail trim double tap  
when you get the boat right move the time slider to the next spot on the bottom, then drag the boat to the next position (you'll see an arrow) rotate, trim, repeat

IMO it's a pain to use right now, but you can do a whole protest form with these digammas and a movie attached to email to the jury so it has potential...

Craig .. I think it's a great start.

As you are editing it, right now the same boat color has the same number.  You'd want that number to increment somehow as you drag subsequent copies of the same color boat.

To Craig Priniski,

Hi,

Have you a link to the App whiteboard? I had a look at the APP but it seems to need a membership log in and I couldn’t see the whiteboard mentioned,  is that correct?

To be clear I have no connection to the app, but I was intrigued when I heard about it!  The app, released by US Sailing is called "Racing Rules" and is probably only in the US App store so you may not find it in the UK  

https://c22sail.com/videos/video/u-s-sailing-racing-rules-app?fbclid=
Link goes to video on using the rules app whiteboard

I have tss for my old PC, but i lost my license when this PC crash... I change for Boat scenario, a version for Mac, very good, some difference with TSS but for those 2 app, we can't illustrate flag for the start. I will try Sail replay this week. You can see some scenario that i make with Boat scenarios last month... on face book https://www.facebook.com/RegatesAuCvl.