ing ▁boat ▁less ▁than ▁ ▁in ▁length ; ▁the ▁smallest ▁boat ▁to ▁take ▁part ▁in ▁the ▁ev acu ation ▁and ▁now ▁preserved ▁by ▁the ▁Imperial ▁War ▁Museum . ▁March ion ess ▁– ▁built ▁in ▁ 1 9 2 3 , ▁in ▁ 1 9 8 9 ▁she ▁was ▁involved ▁in ▁a ▁collision ▁with ▁Bow b elle ▁on ▁the ▁River ▁Th ames ▁with ▁the ▁loss ▁of ▁ 5 1 ▁lives . ▁ ▁– ▁a ▁ 6 , 9 0 0 - ton ▁cargo ▁ship ▁from ▁Glasgow . ▁It ▁was ▁the ▁largest ▁merchant ▁vessel ▁used ▁during ▁the ▁ev acu ation , ▁and ▁was ▁s unk ▁off ▁the ▁beach ▁on ▁ 2 9 ▁May . ▁As ▁it ▁s ank , ▁it ▁happened ▁to ▁sett le ▁even ly ▁to ▁the ▁bottom ▁in ▁shall ow ▁water ▁with ▁the ▁de cks ▁above ▁water , ▁and ▁there after ▁served ▁as ▁an ▁un intent ional ▁de co y ▁target ▁for ▁German ▁Stu ka ▁d ive - b om bers . ▁The ▁British ▁Admir alty ▁later ▁estimated ▁the ▁Cl an ▁Mac Al ister ▁saved ▁over ▁a ▁million ▁pounds ▁( ster ling ) ▁worth ▁of ▁sh ipping . ▁ ▁R N LI ▁lif eb o ats ▁at ▁D unk irk ▁ ▁See ▁also ▁individual ▁stations ▁for ▁more ▁information ▁in ▁many ▁cases . ▁ ▁Ab dy ▁Beau cl erk ▁( ON ▁ 7 5 1 ), ▁a ▁ ▁lif eb o at ▁from ▁Al de burgh ▁L if eb o at ▁Station ▁No . 1 ▁Station . ▁ ▁Cec il ▁and ▁L ilian ▁Phil