From experiance if the bottom of the dagger board case has been broken, then almost certainly the top of the case at the front will also be damaged, the water seems to be forced up the case and any leaks at the top will also allow water to enter. As stated before, its sometimes easier to simply replace the whole case.

Be careful on pressurising the hulls and testing, a very little pressure is a huge force and one needs to be careful not to split the hulls whilst under pressure.

A lot of the Stealth owners have also drilled a small 2 - 3 mm hole through the top pintle and through the hull to prevent a vacumn being formed when the hot air in the hull from sitting in sunlight, is then cooled by immersing it in cold water. The vacumn then pulls in water even through the smallest of pin holes.