install a motorwell throughhull that is not sized for the wall thickness the prior art design having flanges on both ends may have one or both flanges not flush with the wall surfaces to which the motorwell throughhull is mounted or may simply have a nut threaded end arrangement so that the nut and an opposite flanged end can be tightened to the wall surfaces both of these prior art approaches are unaesthetic the first design is difficult to seal with the wall and water may enter into the wall itself and the second design is an impediment to access in order to allow the motorwell throughhull 10 to be sized properly and to be aesthetically pleasing it is provided with a central portion 12 in the form of a threaded nipple structure and first and second end securements 14 or caps each of the securements 14 is preferably of a marine grade material and most preferably is polished stainless steel to provide a quality aesthetic though a colored lacquer for instance may be applied to give the appearance of another metal without degrading the properties of the securements 14 each of the securements 14 includes a flange portion 16 that radially flares outwardly from a tube portion 18 the flange portion 16 has a rear annular face 20 formed around the tube portion 18 the face 20 being substantially flat so as to provide close abutment with a wall w see fig3 to which it is secured the flange portion 16 also has a front surface.