We just took the 45-minute tour a week ago. we have young children (under 9) and that length of tour was perfect for them.
If you're thinking, but you'd practically just get in the boat before it's time to get out, yes, that's what it will feel like to an adult. There is a 2-hour tour that includes looking for seals, etc, for older or more patient tourists.
However, we still saw a lot. The tour leader told us the types of fishing vessels we were passing as we toured Lunenburg Harbour. Then they pulled 3 lobster traps, of different types, near the mouth of the harbour. They brought the catch on board, and banded the claws so we could handle them safely. My children got a kick out of holding lobsters. (They could at the grocery store, I know, but it's different on a boat!)
The guide also had quite a few interesting laminated photos to show while explaining various things. They helped fill in any slow parts of the ride.
They had lifejackets for the children to wear, and lots of the "horse collar" shaped life jackets overhead for adults.
No one needed a washroom, so I have no idea what the washroom looks like.
We would go again on the longer tour when the children are older.