This part of GB/T 19317 specifies the requirements for the manufacture and installation of non-metallic through-hull accessories and/or assemblies used on small boats with a hull length not greater than 24m, including through-hull accessories, sea cocks, soft Pipe fittings and/or drain plugs and their accompanying components. This part of GB/T 19317 does not apply to engine exhaust accessories and sailing connections that penetrate the hull.