Norwegian Cruise Line is raising gratuities on April 1, and one ship, the Norwegian Sky, will have a bigger increase than the others.

Gratuities fleetwide on standard cabins are currently $13.50 per person, per day. The amount for ships other than Norwegian Sky will be adjusted to $13.99, a 3.6% increase. Daily gratuities for standard cabins on the Sky are rising to $18.99, a 41% increase.

Gratuities for suites are $21.99 for the Sky and $16.99 for the rest of the fleet, up from $15.50 currently.

Norwegian said the new gratuity schedule for the Sky was implemented “to better address the demands of the enormously successful all-inclusive product.” The ship, which does short cruises from Miami, has had an open bar since the start of 2016. Beginning in May, the Sky’s four-day cruises will include a stop in Havana instead of the Bahamas.

Norwegian said any guest that has made a booking by March 31, 2017 will have the option of prepaying their service charges at the current rate if done prior to sail date.

The gratuity amounts are automatically added to a guest’s shipboard account. Guests can adjust the rate upward or downward, but only by contacting guest relations at Norwegian after they have returned from their cruise.