I was talking about your problem to some mates of mine who are building RIBs (not in the country) and they have the same opinion as Jon Fuller actually.
They said that once the deck is cut it will not be the same original boat again. This should be your VERY LAST resort.
Is their opinion as well as mine that you should ask an expert who is building RIBs and once they look at your boat they will be able to tell you what is ACTUALLY WRONG with it and give you PROPER advise as to what to do next.
With all due respect to all, I think that the majority of people here (except from VERY FEW) are not experts on building RIBs or anything much really and whatever advise you get needs 3ple verification (trust been there, done that and unfortunately got the T-shirt ) but have learned my lesson.
Now would I get into trouble again??