The first results obtained using two seakeeping computation codes developed
at Ecole Centrale de Nantes (Aquaplus) and at the LEA-Poitiers (Poseidon)
are presented. Both use the diffraction-radiation with forward speed Green
function, but with two different formulations, in a panel code in the frequ
ency domain. Results obtained with both codes are in good agreement and als
o retrieve test measurements or other calculations available. However irreg
ular frequencies and their links with the waterline integral are made evide
nt. (C) 2001 Academie des sciences/Editions scientifiques et medicales Else
vier SAS.