Citing mechanical issues that affect the Carnival Miracle’s maximum cruising speed, Carnival Cruise Lines has canceled 15 of that ship’s port calls in Ketchikan this summer.

According to the Ketchikan Visitors Bureau, the cancellations affect scheduled Sunday port calls beginning May 25th, and include all sailings during the months of June, July and August.

The first three calls, on May 4th, May 11th and May 18th, will remain as scheduled, KVB reports. In addition, the last two calls in September have not been cancelled, but will experience a slight change in arrival and departure times.

The ship carries 2,124 passengers and the cancellations will reduce the number of passengers arriving in Alaska’s First City by about 30,000, based on pre-season estimates.

That brings the total expected cruise passengers coming through Ketchikan down to about 850,000.