RE: My core is not yours
I will be going on vacations to France for 3 weeks starting wednesday, so I don't know when I will check this site again... I have installed my first port this weekend. It fits very well into the existing openeing (you only need to dig in a little where the drains are). It also looks really good. For the galley port: I am not sure if I told you to order a special spigot length of 3 1/4 inch. The galley wall is 3" thick! They have to custom make that port for an additional $40 or so. I had to return mine, and I am waiting for the new one to get in. What kind of head did you install? I am looking into installing a Lavac head. As for your deck core: I am only half surprized that you found delamination on between the lower layer and the core... When I removed some of the ports, I saw that the inner liner was delaminated from the rest of the coach roof at several places. I think that it probably had to do with the way they built the boat: They probably formed the upper and lower portion of the deck seperately, placed the core material on the upper layer, and finally glued the lower portion of the deck (the liner) to the core material. A not so rigourous job would explain why things did not stick too well at several locations... From a structural engineer's point of view: A quick calculations suggest that if the bottom fiberglass layer is not attached to the top one through the core, then the bending strength of the deck is reduced by a factor of 9, and the bending stiffness is reduced by a factor of 28! Outch! (I calculated this assuming two 1/4" layers of fiberglass separated by 1/2" of core). The good news is that I believe that a good portion of any vertical load would be carried to the edge of the hull through arch action (compression) instead of bending action. This is only true because the coachroof is arched. The other good news is that it probably wouldn't take much to restore the full capacity of the deck. The shear force required to bind the inner fiberglass layer to the core is quite low, and reattaching it to the core could only be done at descrete locations. Also, it is likely that the core is still attached at many locations. May be you could just identify where it has come apart and reattach it there. If the area of delamination is smaller than a few square feet, I would not even wory about it: the forces will redistribute. An alternative solution (or an additional preventive measure, since you are heading offshore) would be to build some cross deck beams under the lower fiberglass layer (I plan on doing this too). This would be the benefits: -Large increase in strength and stiffness of the deck -If the beams are attached to the hull, they will also stiffen the hull by keeping both side of the hull from moving relative to each other (hence reduce the load on the hull to deck join). The rig has a tendency to pull the hull side together, while wave action would push them apart (oil canning) -It would be easy to screw several hand rails to these beams. -It would look quite good! Yes, it would be hard work and it would reduce headroom... a trade off. I am planing on installing two of these beams. They would be spaning across the deck from each hull stiffner where the chainplates are attached.
