Euphausiasuperba4,thedragresistanceofthetrawlwashigherandthewidthofthenetmouthwasgreater.(2)Ata/=0.45,thesefactorsinfluencedresistance(Fs)andpowerconsumption(Ps)inthefollowingorder:gravity(A)>crossrope(C)>(B).Theorderoftheirinfluenceonthenetmouthheight(Hs)wasA>B>C,andonenergydissipation(Ce)wasC>A>B.TheoptimalcombinationforhydrodynamicperformancewasA3B3C1.At=0.5,theorderofinfluenceonFs,HsandPswasC>A>B,theorderoftheirinfluenceonCewasB>C>A,andtheoptimalcombinationforhydrodynamicperformancewasA2B3C3.At=0.55,theorderofinfluenceonFsandPswasC>A>B,theirinfluenceonHswasB>A>C,theirinfluenceonCewasB>C>A,andtheoptimalcombinationforhydrodynamicperformancewasA2B3C3.(3)WhenL/Swasextremelylow(0.2),thehorizontalexpansionofthenetmouthwasapproximately23m.Althoughthewidthofthenetmouthwasgreatlyincreased,thetrawlwasinefficientoverallandtherewasasignificantincreaseinthecoefficientofenergydissipation.(4)Themainmethodofadjustmenttoimprovetheoverallperformanceofthetrawlistoincreasetheeffectofgravitybyappropriatelylengtheningtheandthecrossrope.Basedonthisstudy,toachieveahighexpansionofthetrawlatlowtowingspeeds,werecommendtheuseofhighlyexpandableotterdoors.