GRP top - roof rib query

[Boisdevie 2]

I'm renovating a 1976 Harborough Marine narrowboat. The top and sides are GRP. The ceiling has a series of curved ribs that support it. The ribs are made up from pieces of ply cut in a curve and glued together to make a double or in some places a quadruple thick piece. One of these has suffered from rain damage at the end and needs replacing - that's easy enough - but I can 't see how they are fastened into the roof - any ideas?

[X Alan W 223]

IIRC from years back of the ones used by several company's SUC Bijou & Teddesley  the tops were layed up in the outside mould & the pre made roof beams were wriggled into place while the grp lay up was still wet Sorry don't know if the Harbourgh ones were the same

[WotEver 2895]

2 hours ago, X Alan W said:

IIRC from years back of the ones used by several company's SUC Bijou & Teddesley  the tops were layed up in the outside mould & the pre made roof beams were wriggled into place while the grp lay up was still wet Sorry don't know if the Harbourgh ones were the same

That makes sense. I guess if replacing one you'd sit it on resin and then glass over it?

[Boisdevie 2]

thanks for the replies. In this case the ribs are definitely separate from the GRP top. Wonder if I can glue some support struts alongside with sikaflex and then screw into them to support the originals?

[W+T 387]

Can you not just rip out the rotten ones, or all of them and replace with poly foam and laminate over, lot better than ply.  

 

Like this brace/support here.

 

If not as Tony says use timber and lamoinate in place, make it strong as hell to walk on and better than adhesives i would think.