301-10.183—What class of ship accommodations must I use?
         You must use the lowest first-class accommodations when traveling by  ship, except when your agency specifically authorizes/approves your use of other than lowest first-class ship accommodations under paragraphs (a) through (d) of this section.
    
    
    
        
        (b) 
         When use of other than lowest first-class accommodations is necessary to accommodate a medical disability or other special need.
    
    
        
        (1) 
         A disability must be certified annually in a written statement by a competent medical authority. However, if the disability is a lifelong condition, then a one-time certification statement is required. Certification statements must include at a minimum:
    
    
        
        (i) 
         A written statement by a competent medical authority stating that special accommodation is necessary;
    
    
    
        
        (iii) 
         A recommendation as to the suitable class of transportation accommodations based on the disability.
    
    
        
        (2) 
         A special need must be certified annually in writing according to your agency's procedures. However, if the special need is a lifelong condition, then a one-time certification statement is required;
    
    
        
        (3) 
         If you are authorized under  § 301-13.3(a) of this Subchapter to have an attendant accompany you, your agency may also authorize the attendant to use other than lowest first-class class accommodations if you require the attendant's services en route;
    
    
        
        (c) 
         When exceptional security circumstances require other than lowest first-class travel. Exceptional security circumstances are determined by your agency and should only be authorized to the minimum other than lowest first-class travel accommodation necessary to meet the agency's mission. These circumstances include, but are not limited to:
    
    
        
        (1) 
         The use of lowest first-class accommodations would endanger your life or Government property; or
    
    
        
        (2) 
         You are an agent on protective detail and you are accompanying an individual authorized to use other than lowest first-class accommodations; or
    
    
    
        
        (d) 
         When required because of agency mission, consistent with your agency's internal procedures pursuant to  § 301-70.102(i).