What is this number mean?

[Marvin]

I've often seen large numbers installed or painted in the cabin of a sailboat. Often on a board attached to the hull. They have the format 'No. 123456 Net7'. What is this number for? I've tried googleing and can't find anything. Must not be using the right terms.

I'm stumped.

[Jim_ME]

That is the US Coast Guard documentation number for the boat.

Documentation is explained in the first FAQ on this page...
http://www.uscg.mil/nvdc/nvdcfaq.asp#01

[CharlieJ]

And the net 7 is the admeasured tonnage -NOT the displacement of the vessel, but what tonnage it can carry.

[Marvin]

Thanks. That would explain why it was so hard to figure out.

Much appreciated.