The C/B pennant on my Tartan 27' runs through some sort of black hose to the C/B trunk. There is salt water in the bottom of it only.
This boat does not have a trunk in the cabin.
The tube goea down to the top of the keel just below the cabin sole which is about 2 to 3 feet below the waterline.
O'Day 30 - Stuart, FL
Oceanis 411 - South of France