488330  Navigational Services to Shipping 

This U.S. industry comprises establishments primarily engaged in 
providing navigational services to shipping. Marine salvage 
establishments are included in this industry.

The data published with NAICS code 488330 are comprised of these parts 
of the following SIC industries:

    4492 (pt)  Tugboat service (including fleeting and harbor service)
    4499 (pt)  Navigational services