Ice floats because it is expanded water, so a block of ice is less dense than the same volume of water. No matter how many holes you drill in ice (or wood or cork or other materials less dense than water) it will float.
Concrete canoes are very thin-walled boats that have a large interior volume of air - so they are overall less dense than the water they displace. If you bore a hole and replace the air with water, it will be overall more dense than the water and it will sink.
You will note that it was the Titanic that sank not the iceberg in that collision a century ago..The Titanic replaced its volume of air with water and the iceberg was still ice.
It all makes sense now, thank you. I sincerely hope you didn’t think I was being argumentative.
Thanks again for your patience.