The first thing Joseph V. Reed did today as the new U.S. representative on the committee that deals with problems between the U.N. community and its host country was vow that "America has always welcomed the U.N. and continues to welcome the U.N."

Reed, a former Chase Manhattan Bank executive who served four years as ambassador to Morocco, pointedly spoke of "setting sail at this sunrise" with "a big welcome to the hospitality and courtesy of our American shores."

The nautical metaphor is intended to contrast with a warning issued two years ago by a predecessor, Charles M. Lichenstein, that U.N. members who felt unwelcome could leave "and we will be down at dockside waving you a fond farewell as you sail into the sunset."

Reed also appealed to committee members to avoid propagandizing and "overly political debate" because "slam and wham produces a sham."

The second thing Reed did was take cover below deck from angry protests against new American restrictions on the travel of some 450 U.N. staff members from the Soviet Union and five other countries .

The Soviets and their allies, charged that the restrictions, which went into effect 10 days ago, were a violation of American obligations under the U.N. charter.

Reed rejected the charge that the rules violate U.S legal obligations, but said he was willing to listen to suggestions and was "available for a continuing dialogue."

The new American representative's stormy sail into the U.N. seas continued with complaints from Iraq that two of its parking spaces were missing, and from Poland that its diplomats had not yet received cards excusing them from sales taxes.