This paper describes two nautical discoveries buried c.2000 years ago in the Red River alluvial plain, northern Vietnam. One is part of a logboat with a series of empty mortise and locking-peg holes for plank attachment using loose rectangular tenons. The other, from an infant mortuary house, is a series of re-used 4-m-long timbers with exactly the same locked mortise-and-tenon technology. Both finds are interpreted as having belonged to river-boats like those shown on the sides of Heger 1 (Dong Son) bronze drums. Potentially-related technologies from the Mediterranean and China are also discussed.