DIN81915 chock has a simpler structure than JIS 2017-82 type.If comparing their drawings, you can find DIN 81915 doesn't have stiffiners between two sides.There are type C and type D in this mooring pipe group. The difference is not so big that we don't list them here.The other bulwark mounted type of same standard is in another category. When you are checking our website, if any faults, please dont't hesitate to let us know. We will appreciate your support to make us more professional on ship hardware. Meanwhile, we have more details for your reference if you need. Ekaship Hardware Ltd can share with you for free.