Bilge pumps are only designed to pump out the bilges; they won’t cope with a large inrush of water.
Once the weight of water overcomes the buoyancy, down it goes.
I’m sat on my wooden boat which has developed a 10mm hole in the hull, right on the bottom planking. It is quite amazing how much water comes rushing in through such a small hole.
The main bilge pump is keeping well ahead of it now that I have stuffed the hole with rags plus I have 2 other bilge pumps standing by should it get worse.
Now all I need is a diver.