Floating Canopy

Hi all, I'm designing a floating canopy to cover an object, which is 120m in length. Canopy is divided into no.of modules, in which each module consists of two box shaped pontoons of size 9m x 2m x 2m, which are spaced at a distance of 22m. Weight of each module is around 60T. The module's transverse stability is more since the breadth between pontoons is more. But it has negative longitudinal metacentric height. What can I do to make the module longitudinally stable other than increasing the length of pontoon and reducing KG. If the length of the pontoon is made 10m, then GML value is 700mm. I have one more question, GML positive value is enough for stabliity or is there anyr requirement for that? please answer.

 

I'm afraid I'm not understanding what you want to do. Could you please post an sketch?

 

A classic example of a project in serious need of a qualified engineer.

 

How high is the canopy? How much vindpressure to be expected at worst? VCG? etc.. Lot of guessing

 

I used to have a styrofoam sailboat that was extremely unstable, but the manufacturer offset the tendancy to capsize and turn turtle by the addition of a large styrofoam "beach ball" attached to the top of the mast. It didnt sail at all well, but was quite happy to lie on its side on its mooring.
I would like to have seen the design spreadsheet on that brainfart!