Thanks, Adam.
I actually spoke with a manager at The BOATHOUSE myself earlier in the day yesterday and was told they started taking it the day before (Tuesday, 5/19). When I saw what you guys were writing, I changed it up and called Disney Dining and had them put me on hold and call The BOATHOUSE for me to see if they were given the same answer you were - I did this again this morning - and both times they were given the same info I was.
Again, I didn't take the info from Disney Dining as I'm aware that they don't always know what's going on.
One more time lol

I just called again 9:16 am eastern time and spoke to the manager, who informed me that they do NOT take TiW. He said they now take the dining plan as of Tuesday, but they do not take TiW
Please call the restaurant again and asked them directly lol. I hope they do start taking TiW as I have 2 reservations there for the month of July 
Adam