Humber Coastguard has held a public meeting over planned cuts to the service, which they fear would put lives at risk.
The government's modernisation plans include reducing the number of coastguard bases from 18 to eight and the number of jobs from 491 to 248.
Six of the centres, including Humber, which are now manned 24/7 would only be staffed during daylight hours.
Coastguards in Humber said the plans were "seriously flawed".
Paul Chapman, of Humber Coastguard's Watch Office, said: "We at Humber Coastguard believe that the modernisation plans are seriously flawed, and are concerned for the safety implications to the mariner and coastal user in our area of operation - the River Humber to the Scottish Border."
The Department for Transport has said that improvements in communications and technology will enable a "more effective, efficient coastguard" to emerge.
A public consultation runs until 24 March and a meeting was held a Bridlington Spa on Monday night.
The Humber Coastguard has also set up an online petition, which has more than 200 signatures.