If you travel with a t:card on a passenger boat or ferry, you can travel and refill your t:card just as before and will not use the new online store yet.
Transfer to and from bus
If you travel by bus in connection with your boat trip, you will not be able to validate your t:card on board the bus from August 7th. During this period, you must present a receipt for the purchase. Print a receipt from the online store or bring a receipt from the purchase on board and show it to the driver.
Have you tried the app AtB Mobillett?
With the the app AtB Mobillett you can easily show your ticket on both bus and boat.