GWN, Now you see why I was cautious about sharing info w/your h's daughter. I have a feeling that had you said something about the boat or shared additional informatiion about you and your h, she would have carried the info right back to him. A person that brings info, most likely will carry info back.
I have an additional thought to add to the one's that Kaffe mentioned...maybe your h told his daughter about the boat, hoping that she would break the news to you so that you wouldn't be angry about it and have time to settle down. Sometimes mlcers manipulate others to do their bidding and he may have done that so that she could go back and tell him your reaction.
Now, that you have the information, you need to sit down and think about how you are going to handle this. If it violates the separation agreement, you will need to take action. Do not allow this to slip through the cracks because if you do, he will think it is okay to do whatever he wants w/o discussing it w/you. I would wait until the trip to see if he brings it up. If he doesn't, you will need to pick a time and discuss it w/him.
There are any number of reasons why he's sharing info w/his daughter and we could sit here all day trying to rationalize why he's doing what he's doing. However, that will not resolve the issue of the boat sale for you. GWN, time to think about what you want to do and when.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
