I'm still working on my lingo..but there's the 6-16's and the D2's also.
I think tjl is referring to DB's that conform to IDBF specifications in terms of length, width and weight requirements. There are many variations of DB's, but 6-16, D2's, Milleniums, Dynasty versions of DB's do not meet those spec's.
To answer tjl's post, I've paddled in the SRS DB's....they were used at 2006 CCWC's.
http://www.simonriversports.com/english/products/dragon%20boat/dragon.html