I have a dock that is made of ipe and a type of iron bark (not sure which one, but it was expensive and supposed to have been resistant to marine borers). It has suffered severe damage from marine borers and we are thinking of replacing it and are discussing options. I'm leaning toward some sort of fiberglass or plastic material, but cost may prove prohibitive. The dock is two pontoons, 3 feet by 16 feet, with a submerged section that is 10 feet by 16 feet that is ramped to shore to accommodate the tide changes. Flotation is from 16 30 gallon barrels built into the pontoon sections. After reading the Knowledge Base articles on the subject, it seems that if we go with some sort of wood product, the best way to treat it is with copper arsenate and then creosote. Where is this type of treated wood available and are there any other options?
(Sawing and Drying Forum)
From Professor Gene Wengert, forum technical advisor:
Almost every saltwater marine dock and pier repair facility will have the material you need. It is our only option when using wood in this high risk environment. Note that CCA is approved for this use still.
After 18 months, all of the new pilings had been substantially damaged by the shipworms, and all of them had to be replaced. The University of Maine offered up some solutions of fiber reinforced plastics, but I think in the end the city went with imported greenheart pilings, and there has been no damage since.