which rules should i select

there is a tug boat need to naturalization abs classification.
which abs rules should i see?

 

I don't know what does the expression "naturalization abs classification" mean.
But the rules to be followed are generally chosen by the shipowner and is declared in the SOR (Statement of Requirements).

 

The ABS Rules are subdivided by vessel length and type of service.

For a small vessel like a tug, there are a couple of different ABS rules which could apply:

1. Steel Vessels for Service on Rivers and Intracoastal Waterways
2. Steel Vessels under 90 Meters in Length

(1.) would apply to a tug not intended to go offshore, like a harbor tug. (2.) would be used for a tug which would go offshore and possibly be large enough to require a load line, like a large salvage tug or a tug to be used to transport large floating objects between ports.