The bad news is that the Navy’s Rim of the Pacific exercises are bringing crowds, added aircraft noise and some faulty garage door activity through the end of July.

The good news is an initial $52.5 million boost to Hawaii’s economy, based on the number of exercise participants and time in port, with an impact of tens of millions more expected after purchases of supplies, fuel and food, and spending by family and friends of participating personnel are figured in, according to Navy Region Hawaii.

Twenty-six nations, 45 ships, five submarines, more than 200 aircraft and 25,000 personnel will participate in the biennial RIMPAC exercise, which got underway Thursday and wraps up Aug. 4, mostly in and around the Hawaiian Islands but also in Southern California.

Ships from participating nations are flooding into Pearl Harbor this week.

“RIMPAC brings international participants together to foster and sustain cooperative relationships,” the Navy said. “Training during RIMPAC builds credible, ready maritime forces that help to preserve peace and prevent conflict.”

Exercise locations include Joint Base Pearl Harbor-Hickam, Marine Corps Base Hawaii at Kaneohe Bay and the Pacific Missile Range Facility on Kauai.

“Hawaii’s operating areas and ranges offer realistic, relevant training opportunities like nowhere else in the world and environmental stewardship and protection of marine mammals are always top priorities during RIMPAC,” the Navy said in a news release.

During the in-port portion of the exercise, crews receive training on sighting marine mammals and required protective measures, the Navy said.

However, environmental law organization Earthjustice said the mammoth exercise “will have devastating impacts on marine life.”

The use of sonar and explosives in military training exercises at sea have been proved to pose great risks to marine mammals, Earthjustice said.

“The scientific evidence is overwhelming. Past RIMPAC exercises may have contributed to mass-strandings of whales,” the organization said. “The Navy itself estimates that training off the coasts of Hawaii and Southern California could result in the deaths of as many as 155 marine mammals and the permanent injury of more than 2,000 more over a five-year period.”

The Navy should cease these activities in sensitive marine mammal habitat, Earthjustice said.

The Navy also addressed the phenomenon of some garage door remote controls not working during RIMPAC, which has been noted before.

“This can occur if the device is a type (FCC-regulated but unlicensed Part 15) that operates on frequencies reserved for federal government systems,” the Navy said. Those devices can be affected by electromagnetic activity generated by Navy ships, civilian boaters or other sources.

The Navy said it is required to test commercial surface-search radars in port before getting underway and as part of scheduled maintenance. Surface-search radars are available commercially, used by civilian boaters and not a safety issue.

Engineers say garage door openers have a radio frequency that decodes information from a transmitter, and a high level of radio frequency, or RF, can jam a receiver. Military radars or communications can cause interference by drowning out weaker signals.

If a remote control isn’t working, the Navy said to remove it from the vehicle’s sun visor and point it directly at the door. If the opener still doesn’t work, the garage door might have to be opened and closed manually, or other options considered, for a short time.