I would do it in two steps:
1) Fasten the two sides together with a slow CA
2) Fill in the seam with a slow set epoxy
The reason for the two step method is that the CA will give a little time to position the sides and then hold almost instantly, making a quick build. The problem with CA is it's brittle so it won't handle the additional stress you were refering to. Backfilling the seam with epoxy will give you the stress resistance CA won't and at the same time will increase the hulls strength considerably. I would test the epoxy on a parts tree first to make sure it won't eat the plastic since I know the Kearsarge is a somewhat rare kit. I got lucky in finding the kit I have, almost 10 years after buying the Cutty Sark, Alabama and Constitution. When I found it, I had to buy it to complete my set
