Yep it is serious. You need to fix this prior to going out again. It's better to do both sides but I would probably do one side very strong.

1. Cut a hole for a 6 inch port. Do not install the port until after the fix.
2. Sand the area to be fixed with 100 grit paper. About 6 inches on either side of the crack. Sand good so that your repair sticks. If the repair fails it most likely will fail because the repair doesn't bond to the material in the hull properly because it was not sanded enough or not clean enough (dust).
3. Clean the entire area of dust with Acetone or MEK.
4. Buy some West System Epoxy and carbon fiber. Cut into strips starting with about 3 inches wide then about 4 inches then 5 inches to cover the entire crack and extend past the crack a good 6 inches in all directions.
5. Mix the epoxy according to directions. Make sure you are doing this on a day that is neither too hot or too cold. Make sure the epoxy is not hot from sitting in a car or something. Perfect is about 70-80 degrees.
6. Use a disposable foam brush. Brush the area on the boat to be laid up. Put the the first layer of 3 inch strips down. Brush again. Put next layer down. Brush gain. .... Put last layer down. Brush again.

7. Let it sit for 24 hours. Check to make sure the epoxy is hard and has gone off.
8. Install the new deck port.

You can substitute A good weave glass and polyester resin. I would be very temped to do this. However I would use a few more layers to be sure it is strong. You definitely only need to do one side if you do the repair strong.

Mike Hill
Tiger #1520