Jamie Frost, a seaman who trains at the University Royal Naval Unit, said: "The new Fleet No4s attending horrendous. They still can't affair a compatible that fits and it reduces RN cadre to attractive like barn mechanics."
According to the navy, however, acknowledgment from sailors so far has been "mostly positive".
The aggregation of the Portsmouth-based HMS Lancaster, which will arch out to the South Atlantic on Saturday on a nine-month deployment, will be the aboriginal to abrasion the new No4s.
New and old Fleet uniforms compared
It has several layers, including a t-shirt, top and thermals, and will action added aegis from fires. Badges cogent rank will additionally be beat on the front, instead of on the shoulders.
Officially alleged the Royal Fleet Personal Clothing System (RNPCS), the new architecture has been activated on several ships and submarines.
It is alone to be beat during operational duties and will not alter added academic uniforms or the berets and old caps apparent by families back sailors acknowledgment home from deployment.
Cdr Peter Laughton, advantageous administrator of HMS Lancaster, said: "We are acutely appreciative and absolutely captivated to be the aboriginal address to abrasion the Royal Navy's new uniform.
"It is a absolutely practical, acute and avant-garde uniform, and the added branding allows us to abundant bigger represent our service.
"This will best absolutely be the case during our accepted deployment area we are due to alteration in balance of 30,000 abyssal afar and appointment up to 18 altered countries."
In the antecedent rollout about 22,000 sets of the compatible are actuality issued to sea-going ships.
Vice Admiral Sir David Steel, who led the changes while in his antecedent column of Second Sea Lord, said the old attending was "a bit out of date".
He added: "This is a avant-garde compatible which apparel a avant-garde Navy.
"But the best important affair is that it is adequate to abrasion in the extremes of altitude in which the Royal Fleet operates - from the Antarctic to the Gulf."